0:00:02 > 0:00:05Welcome to Australia. We're in the Blue Mountains just west of Sydney
0:00:05 > 0:00:09in New South Wales, and we're here at the peak of the wildfire season.
0:00:09 > 0:00:11We've been given incredible access
0:00:11 > 0:00:13to one of the world's biggest firefighting forces
0:00:13 > 0:00:15at its busiest time of the year.
0:00:15 > 0:00:21Every year, they battle thousands of fires in an area larger than France.
0:00:21 > 0:00:24We're following their operations to discover why wildfires
0:00:24 > 0:00:27are so frequent and so hard to control.
0:00:27 > 0:00:31- Oh, look out! Low side of the road! - Whoa, whoa, whoa, whoa!
0:00:32 > 0:00:35Last time, we revealed how fires ignite
0:00:35 > 0:00:39and the astonishing ways they can spread.
0:00:39 > 0:00:42Ooh! Erupts at the bottom.
0:00:42 > 0:00:45The lightning channel generates a big pressure wave
0:00:45 > 0:00:47and it's actually like fireballs.
0:00:47 > 0:00:50And we explored the vast infrastructure put in place
0:00:50 > 0:00:53to spot fires and stamp them out fast.
0:00:53 > 0:00:58You're standing here looking at battles breaking out.
0:00:58 > 0:01:01In this programme, we'll investigate why the wind
0:01:01 > 0:01:03can be a firefighter's worst enemy.
0:01:03 > 0:01:06This fire could go 40km or more,
0:01:06 > 0:01:09and it could actually impact on people's properties.
0:01:09 > 0:01:13We'll uncover the causes of the most extreme fires.
0:01:15 > 0:01:17By drawing air in just through those gaps,
0:01:17 > 0:01:21that causes the rotating motion that spins up to a high velocity.
0:01:22 > 0:01:28We'll find out about an unexpected technique for controlling fires.
0:01:28 > 0:01:29Whoo!
0:01:29 > 0:01:32Between 20 and 30 seconds gives them plenty of time to clear
0:01:32 > 0:01:35the helicopter and actually be on the ground when they catch on fire.
0:01:35 > 0:01:37I can see how they're effective.
0:01:37 > 0:01:41And we'll meet scientists unlocking the secrets of fire behaviour
0:01:41 > 0:01:42to help those on the front line.
0:01:42 > 0:01:47- We can already smell a little bit of...- Oh, look, and actually it's starting to smoke.- It's slightly...
0:01:47 > 0:01:48What is smoking?
0:01:48 > 0:01:51Lessons learnt in Australia are helping firefighters
0:01:51 > 0:01:54tackle wildfires across the world.
0:01:54 > 0:01:57Join us as we go inside the wildfire.
0:02:06 > 0:02:08Wildfires are a global phenomenon
0:02:08 > 0:02:11raging across six of the seven continents,
0:02:11 > 0:02:13wiping out millions of acres of land
0:02:13 > 0:02:15and affecting hundreds of thousands of people,
0:02:15 > 0:02:19and New South Wales is one of the worst-affected areas on Earth.
0:02:19 > 0:02:22During the height of the wildfire season here,
0:02:22 > 0:02:23from October through to February,
0:02:23 > 0:02:28this state can be hit by more than a hundred fires a day.
0:02:28 > 0:02:30We've come here in January -
0:02:30 > 0:02:33it's the peak of summer, and the peak of the fire season.
0:02:33 > 0:02:37I'm with fire crews in the remote Wollemi National Park,
0:02:37 > 0:02:39working to bring a new fire under control.
0:02:40 > 0:02:43It's hardly rained here for ten weeks
0:02:43 > 0:02:47and with temperatures in the 30s and winds regularly in excess of 30km/h
0:02:47 > 0:02:51current conditions are perfect for wildfires.
0:02:51 > 0:02:53Crusty, how far are we from the fire now?
0:02:53 > 0:02:57Yeah, Simon, the fire's about 4km to the east of us now,
0:02:57 > 0:03:00it's up on top of this escarpment.
0:03:01 > 0:03:03'David Crust, known as Crusty,
0:03:03 > 0:03:06'is coordinating the firefighting response.'
0:03:08 > 0:03:10There's a great fog of smoke down there,
0:03:10 > 0:03:13but I can see the fire through the trees.
0:03:13 > 0:03:16'This is the biggest wildfire I've seen since I arrived.'
0:03:16 > 0:03:18How do you think this fire started?
0:03:18 > 0:03:21This is a lightning strike from about eight days ago
0:03:21 > 0:03:25and obviously it hit a tree, the tree ignited,
0:03:25 > 0:03:27and a branch has dropped out of the tree
0:03:27 > 0:03:29and it's ignited the fields underneath.
0:03:29 > 0:03:33It's almost like a fire time bomb - burning away gently, quietly,
0:03:33 > 0:03:39and then all of a sudden it drops a branch and a fire erupts.
0:03:39 > 0:03:42That's why we have to be so vigilant.
0:03:42 > 0:03:45'The fire was first spotted by Crusty two hours ago.'
0:03:46 > 0:03:48When we got here this morning, it was making a run.
0:03:48 > 0:03:49What do you mean by that?
0:03:49 > 0:03:52Well, it had an uphill run so it was pre-drying the fields.
0:03:52 > 0:03:54It had the wind behind it,
0:03:54 > 0:03:57so the fire was really behind it quite intensely.
0:03:57 > 0:04:01The topography of the landscape it inhabits is a major influence
0:04:01 > 0:04:02on how a fire behaves.
0:04:06 > 0:04:10When a fire reaches an uphill slope, the heat and smoke rises,
0:04:10 > 0:04:14drying out vegetation ahead which then ignites and burns more rapidly.
0:04:17 > 0:04:19The speed of a fire can double
0:04:19 > 0:04:21with every ten-degree increase in incline.
0:04:25 > 0:04:28So far, the fire has travelled 6km.
0:04:28 > 0:04:30The combination of wind and uphill terrain
0:04:30 > 0:04:33means it could easily gain momentum and spread much further.
0:04:35 > 0:04:37What are your concerns about this fire? What could go..?
0:04:37 > 0:04:41- What could happen with it? - This fire could go 40km or more.
0:04:41 > 0:04:44- And it could actually impact on people's properties.- 40km?
0:04:44 > 0:04:47Ah, it would travel 40km in a day, potentially,
0:04:47 > 0:04:51and then we'd have weeks and weeks of work to contain it.
0:04:53 > 0:04:56The potential speed at which this fire could travel
0:04:56 > 0:04:59means Crusty has called in aerial reinforcements
0:04:59 > 0:05:01from across the state to attack the fire front.
0:05:04 > 0:05:07We've got a bucket going in now just beneath us.
0:05:07 > 0:05:10So, the red helicopter is working with the ground crew,
0:05:10 > 0:05:13so the boys on the ground are on the radio
0:05:13 > 0:05:16and they're calling in that drop, and they're talking it in.
0:05:22 > 0:05:25There it goes. He's dropping the water now.
0:05:25 > 0:05:26Look at the skill involved in that.
0:05:26 > 0:05:30There was real, absolute... It's a surgical strike, really.
0:05:30 > 0:05:34So you've had how many helicopters on this today?
0:05:34 > 0:05:36Six helicopters here today.
0:05:36 > 0:05:39Six helicopters, and how many, how many fire-fighters on the ground?
0:05:39 > 0:05:41Got over 20 guys on the ground
0:05:41 > 0:05:44working very hard to stay on top of this.
0:05:48 > 0:05:52'Each bucket can scoop up as much as 650 litres of water.
0:05:53 > 0:05:57'They take it from wherever they can get it - creeks, rivers,
0:05:57 > 0:06:00'billabongs, and even people's swimming pools.
0:06:01 > 0:06:04'Dropping water from aircraft was pioneered by the Canadians during
0:06:04 > 0:06:08'the Second World War and adopted by the Australians in the 1960s.
0:06:10 > 0:06:13'To cope with this year's fire season, the RFS have had to
0:06:13 > 0:06:18'expand their water-bombing fleet from 26 to 138.'
0:06:20 > 0:06:24And that's the most effective method of getting a fire out?
0:06:24 > 0:06:27Absolutely, it's all about getting water on the ground.
0:06:27 > 0:06:30'Even if they manage to bring the fire under control
0:06:30 > 0:06:33'this afternoon, the logistical challenges of getting fire-fighters
0:06:33 > 0:06:37'into this remote location mean it could take days to extinguish.
0:06:39 > 0:06:41'And this is just one of three fires
0:06:41 > 0:06:44'within the park they're tackling at the moment.
0:06:44 > 0:06:47'Already this season, the fire fight in the Wollemi has cost
0:06:47 > 0:06:49'almost £5 million.'
0:06:51 > 0:06:54This has been a really busy fire season, been a lot of fires
0:06:54 > 0:06:56and large areas of burn.
0:06:56 > 0:06:58So that's a one-in-ten-year event.
0:06:58 > 0:07:00One-in-ten-year event?
0:07:00 > 0:07:03So you haven't seen it like this for nearly a decade?
0:07:03 > 0:07:06No, the, the conditions are just so dry.
0:07:06 > 0:07:09I mean, we've been at this for about 12 weeks straight now,
0:07:09 > 0:07:11so it's been a tough season.
0:07:11 > 0:07:13It sounds exhausting.
0:07:13 > 0:07:16Er, yeah, we're all looking forward to some rain and a rest.
0:07:21 > 0:07:24'While Crusty's team use water-bucketing to control
0:07:24 > 0:07:27'the fire in the Wollemi, 100km to the southwest,
0:07:27 > 0:07:31'fire-fighters near the city of Bathurst are also dumping
0:07:31 > 0:07:35'water on flames, but on a much bigger scale.'
0:07:36 > 0:07:40This fire is one of three in the area started by a lightning storm.
0:07:42 > 0:07:45Winds have been gusting at 40kms per hour, and have driven the fire
0:07:45 > 0:07:49to within 30km of Bathurst and its population of 38,000.
0:07:53 > 0:07:57The winds are expected to return this afternoon, and with people
0:07:57 > 0:08:00at risk, heli-bucketing alone isn't sufficient defence.
0:08:03 > 0:08:06So they've called in the most effective water-dropping weapon
0:08:06 > 0:08:08in the Rural Fire Service fleet.
0:08:09 > 0:08:13This beast behind me is known as the Skycrane,
0:08:13 > 0:08:16it's the ultimate weapon in fighting wildfires.
0:08:16 > 0:08:22It can suck up 9,000 litres of water in just 15 seconds.
0:08:23 > 0:08:27It's thanks to these that the whole of New South Wales
0:08:27 > 0:08:29is not on fire right now.
0:08:34 > 0:08:36'With a top speed of 200 kms/hr
0:08:36 > 0:08:41'and a range of 400km, this helicopter is unrivalled in its
0:08:41 > 0:08:45'ability to get right to the heart of a fire fast and effectively.
0:08:45 > 0:08:48'There are three in active service across New South Wales -
0:08:48 > 0:08:54'they deliver the equivalent of 14 heli-buckets of water in one hit.
0:08:54 > 0:08:58'They're deployed daily across the state to attack whichever fires
0:08:58 > 0:09:00'pose most threat to life and property.'
0:09:02 > 0:09:05It's out here that you really see the Skycrane come into its own.
0:09:09 > 0:09:12It looks like such an unwieldy beast of a machine,
0:09:12 > 0:09:16but in the hands of a skilled pilot it's incredibly manoeuvrable.
0:09:18 > 0:09:22It's coming in now to the dam to refill...
0:09:23 > 0:09:27..and he hovers like a giant dragonfly above the water,
0:09:27 > 0:09:30and you can see the snorkel going in, sucking up
0:09:30 > 0:09:33that 9,000 litres in seconds.
0:09:43 > 0:09:47And off he goes, following the line of the valley...
0:09:49 > 0:09:54..and approaching the areas of forest that are still smoking.
0:09:54 > 0:09:57There are flames beneath the canopy.
0:09:57 > 0:09:59And then he does his drop,
0:09:59 > 0:10:01a great curtain of water...
0:10:03 > 0:10:07..hitting the smoke with astonishing accuracy.
0:10:11 > 0:10:15'It's hoped that the Skycrane can reduce the size of the fire
0:10:15 > 0:10:17'before the winds pick up later.
0:10:17 > 0:10:22'Just a twofold increase in wind speed could quadruple the rate
0:10:22 > 0:10:23'at which the fire spreads.
0:10:35 > 0:10:37'To find out more about why wind
0:10:37 > 0:10:39'is such a critical factor in fire behaviour,
0:10:39 > 0:10:44'I'm going back to the Rural Fire Service headquarters in Sydney.
0:10:46 > 0:10:50'From here, they're monitoring the hundreds of fires that can
0:10:50 > 0:10:52'occur at any one time.
0:10:52 > 0:10:56'They make minute-by-minute decisions about where to send
0:10:56 > 0:10:58'aerial resources like the Skycrane
0:10:58 > 0:11:02'and a 70,000-strong crew of volunteer fire-fighters.
0:11:04 > 0:11:08'Key to this process is in-house weather forecaster Simon Lewis.'
0:11:10 > 0:11:12Weather really is critical for determining fire behaviour
0:11:12 > 0:11:15and fire activity, so we look at the temperature,
0:11:15 > 0:11:17how dry it is, how windy it is.
0:11:17 > 0:11:20We're expecting an easterly surge in the winds just over
0:11:20 > 0:11:24the southern ranges tomorrow. The stronger the winds we get,
0:11:24 > 0:11:26the faster that pushes the fire flanks along,
0:11:26 > 0:11:29and so you get faster rates of fire-spread.
0:11:31 > 0:11:35To understand the impact of wind on a fire, you first need to know that
0:11:35 > 0:11:40all fires move with a common shape and that it's not a straight line.
0:11:42 > 0:11:45The hottest and quickest-moving part of the fire
0:11:45 > 0:11:46is known as the front...
0:11:48 > 0:11:51..while the sides or flanks burn more slowly
0:11:51 > 0:11:53and less intensely.
0:11:54 > 0:11:58Once a fire has ignited, the wind can control the speed
0:11:58 > 0:12:02at which it moves, and determine in which direction it travels.
0:12:03 > 0:12:05For Simon, keeping a close eye on wind direction,
0:12:05 > 0:12:09especially any sudden changes, is vital.
0:12:09 > 0:12:12One of the things I will do in here is track the position
0:12:12 > 0:12:15of wind changes as they move across the state,
0:12:15 > 0:12:18and I'll also monitor when we're expecting those to reach particular
0:12:18 > 0:12:21fire grounds, which is really important for fire-fighter safety.
0:12:21 > 0:12:24For Rob Rogers, the man in charge of operations
0:12:24 > 0:12:26at the Rural Fire Service,
0:12:26 > 0:12:29a rapidly changing wind is his worst nightmare.
0:12:29 > 0:12:32You'll get fire-fighters operating on a side of a fire,
0:12:32 > 0:12:35because often when it's really burning very hot
0:12:35 > 0:12:37you can't put them at the front, it's just too dangerous,
0:12:37 > 0:12:40so they'll go on the, what we call the flanks of the fire.
0:12:40 > 0:12:43If there's a sudden wind change and the side becomes the front,
0:12:43 > 0:12:47and you've got people sitting there, it's a really dangerous area,
0:12:47 > 0:12:50and they call it the dead man zone, because in the past,
0:12:50 > 0:12:53there have been fire-fighters killed in that sort of circumstance.
0:12:53 > 0:12:56'It was a sudden shift in wind direction that helped to
0:12:56 > 0:13:00'create one of the worst fires Australia has ever seen.
0:13:00 > 0:13:03'Simon's going to meet a couple who managed to survive
0:13:03 > 0:13:07'the full force of this blaze to discover just how rapidly a fire
0:13:07 > 0:13:09'can change its behaviour.'
0:13:09 > 0:13:11Let me just show you this, actually.
0:13:15 > 0:13:17Can you see the sign here?
0:13:17 > 0:13:22They have these outside almost every community in this part of Australia.
0:13:22 > 0:13:25It's such a graphic illustration of the threat.
0:13:25 > 0:13:29Everybody's conscious of it, fire danger today very high.
0:13:32 > 0:13:35It was extremely hot conditions like this that led to huge numbers
0:13:35 > 0:13:38of fires in the neighbouring state of Victoria
0:13:38 > 0:13:40on Saturday 7th February 2009.
0:13:42 > 0:13:46More than 300 grass and bushfires swept across the state
0:13:46 > 0:13:50and around the city of Melbourne and its population of four million.
0:13:51 > 0:13:54One fire which began at Kilmore East was being driven
0:13:54 > 0:13:56southeasterly by strong winds.
0:14:00 > 0:14:0330km away was the town of Kinglake West...
0:14:05 > 0:14:07Ruth, Jason, hello.
0:14:07 > 0:14:11'..home to Jason and Ruth and their two children.
0:14:13 > 0:14:16'They'd lived in Kinglake West for 12 years.
0:14:18 > 0:14:20'Weather conditions that day were exceptional,
0:14:20 > 0:14:23'with temperatures in excess of 40 degrees by 11am.'
0:14:25 > 0:14:28It was the hottest day ever, ever I've seen up here,
0:14:28 > 0:14:31and the wind, we could hardly even stand up.
0:14:31 > 0:14:34It was that strong, the wind.
0:14:34 > 0:14:37'With the fire closing in on their house, the couple had to make
0:14:37 > 0:14:41'a stark choice - evacuate or stay and prepare to defend their home.'
0:14:42 > 0:14:45When you've got two children, one still in nappies...
0:14:47 > 0:14:50..you've got to make a serious decision right on the spot
0:14:50 > 0:14:53and think, 'Well, what am I going to do?'
0:14:53 > 0:14:55So I decided I had to go.
0:14:55 > 0:14:58'Ruth put the kids in the car and headed away from their home,
0:14:58 > 0:15:00'but Jason decided to stay and defend.'
0:15:02 > 0:15:04I'd seen it come from that direction, I could hear it first,
0:15:04 > 0:15:09like a storm, and the roar, and things actually starting to explode.
0:15:09 > 0:15:12It wasn't much smoke at all, it was just fire, it was all
0:15:12 > 0:15:15riding on the top and it was like the air was on fire as well,
0:15:15 > 0:15:19because you could... I can still almost smell it, it's like...
0:15:19 > 0:15:21the burning oil, burning eucalyptus,
0:15:21 > 0:15:24that was like above the trees on fire.
0:15:27 > 0:15:30'Jason is describing what's known as a crowning fire.
0:15:34 > 0:15:37'Flames leap from the ignited leaf litter on the ground
0:15:37 > 0:15:38'up to the tree tops.
0:15:38 > 0:15:43'Exposed to the full force of the wind, fire then spreads at terrifying
0:15:43 > 0:15:48'speeds across the canopy, up to four times faster than a ground fire.
0:15:54 > 0:15:57'At around six o'clock that evening, the wind changed direction,
0:15:57 > 0:15:59'blowing the fire eastward...
0:16:02 > 0:16:03'..and the flanks of the fire,
0:16:03 > 0:16:06'stretching up to 55km in length,
0:16:06 > 0:16:11'suddenly became a huge fire front heading straight for Kinglake West.'
0:16:12 > 0:16:14I'd seen the hay shed go up,
0:16:14 > 0:16:18and then when it got really intense I was actually using the hose
0:16:18 > 0:16:22against the wind just to, to stop myself from...
0:16:22 > 0:16:24- Perishing. - Yeah, just being burnt, you know?
0:16:24 > 0:16:28I was just holding it like at the flames, or at the front as it
0:16:28 > 0:16:31kept coming, by now there were a lot of embers and stuff starting
0:16:31 > 0:16:35to come as well, just holding it, you know, and then turning round
0:16:35 > 0:16:39again and trying to spray the house, cos it was just drying on it.
0:16:39 > 0:16:41That's when my hose failed.
0:16:43 > 0:16:47'With some fires travelling up to 600m in 30 seconds,
0:16:47 > 0:16:50'the fire wreaked devastation through community after community.
0:16:57 > 0:16:59'Thick black smoke in some areas
0:16:59 > 0:17:02'meant water-bucketing helicopters were grounded.'
0:17:04 > 0:17:05Everything was on fire,
0:17:05 > 0:17:08I couldn't think of anywhere else I could shelter.
0:17:08 > 0:17:11I headed for the dam and I crawled down until I could feel
0:17:11 > 0:17:16the water, and I turned round backwards and went in backwards
0:17:16 > 0:17:20with my head out just on the bank, and that's where I just laid there.
0:17:21 > 0:17:24'As soon as the fire had passed through, a major rescue operation
0:17:24 > 0:17:28'was under way in the most appalling conditions.'
0:17:28 > 0:17:31I remember the voices, and then I heard him say,
0:17:31 > 0:17:33"Is someone down here?"
0:17:35 > 0:17:39And I couldn't hardly move, but...
0:17:41 > 0:17:45..I remember the feeling of the gloves they wear on my face,
0:17:45 > 0:17:48and he held me hand and he said, "Can you squeeze my hand?"
0:17:48 > 0:17:50And I squeezed his hand and he said,
0:17:50 > 0:17:54"If you can squeeze my hand that means you'll make it."
0:17:54 > 0:17:55Yeah.
0:17:55 > 0:18:00There's very few natural events that could transport you
0:18:00 > 0:18:03- so immediately from... - Hmm-mm.- Hmm.
0:18:03 > 0:18:06- ..paradise to hell, really. - Yeah, that's right, yeah.
0:18:08 > 0:18:12'Jason is extremely lucky to have survived an event that has
0:18:12 > 0:18:13'become known as Black Saturday.
0:18:15 > 0:18:19'Throughout Victoria, 173 people lost their lives,
0:18:19 > 0:18:22'and more than 2,000 homes were destroyed.
0:18:22 > 0:18:26'The sudden wind change was one of the factors that made the fire
0:18:26 > 0:18:30'so hard to control, and it wasn't only residents that were caught out.
0:18:32 > 0:18:36'Many fire-fighters also found their escape routes cut off.
0:18:39 > 0:18:43'Six fire trucks were caught in burn-overs when the fire front
0:18:43 > 0:18:46'passed directly over them, engulfing the trucks in flames.
0:18:47 > 0:18:50'Fortunately, all the fire-fighters inside survived.
0:18:52 > 0:18:56'The incident motivated Australian scientists to carry out
0:18:56 > 0:18:58'the kind of critical research Kate's on her way to see
0:18:58 > 0:19:02'at the Rural Fire Service Hot Fire Testing Centre in Mogo.'
0:19:07 > 0:19:10'This is a Cat 7 fire truck.
0:19:10 > 0:19:14'There are 1,200 in active service throughout New South Wales.
0:19:17 > 0:19:20'Today, lead researcher Justin Leonard is using
0:19:20 > 0:19:23'the only bushfire simulator of its kind in the world
0:19:23 > 0:19:27'to subject the Cat 7 to an artificial burn-over.
0:19:27 > 0:19:29'He's invited me to join him
0:19:29 > 0:19:33'while he measures the levels of heat and smoke within the vehicle.
0:19:33 > 0:19:36'These indicators help to assess what conditions
0:19:36 > 0:19:39'are like for fire-fighters as a fire strikes,
0:19:39 > 0:19:41'but this is the first time
0:19:41 > 0:19:45'he's done it with anyone actually seated inside the cab.'
0:19:48 > 0:19:51It's quite an odd mental process preparing yourself to
0:19:51 > 0:19:55knowingly go into a burning truck, or at least one that's going
0:19:55 > 0:19:58to be close enough to be very, very hot and uncomfortable.
0:19:59 > 0:20:01I have no idea what it's going to be like.
0:20:01 > 0:20:05I know... You know, you know about radiation, about radiated heat,
0:20:05 > 0:20:08you light a fire at home, you can feel it,
0:20:08 > 0:20:13but the idea of being stuck in a very small confined space
0:20:13 > 0:20:17with the heat ever-increasing is terrifying.
0:20:18 > 0:20:21But I'm sort of fascinated by the process as well, I'm kind of...
0:20:21 > 0:20:23I have no idea how I'm going to react,
0:20:23 > 0:20:28whether I'm going to completely panic or feel quite calm.
0:20:28 > 0:20:29Um, just don't know at this stage.
0:20:33 > 0:20:36'Justin has placed a number of sensors around this fire engine
0:20:36 > 0:20:40'to monitor temperatures in and out of the cab and keep us safe.
0:20:40 > 0:20:43'41 gas burners surrounding the truck
0:20:43 > 0:20:47'will recreate the different stages of the burn-over.'
0:20:51 > 0:20:54- Right, how are you feeling? - Um, a bit nervous,
0:20:54 > 0:20:58I wouldn't say my heart rate's at resting pace right now.
0:20:58 > 0:20:59No, mine neither!
0:21:01 > 0:21:03- Shall we get it over with? - Yeah, good luck.
0:21:03 > 0:21:05Thank you, you too.
0:21:05 > 0:21:06Let us know how you're feeling
0:21:06 > 0:21:10- in terms of the radiant heat load on your skin.- OK.
0:21:10 > 0:21:14OK, Martin, we're ready for the low stage of the burners.
0:21:14 > 0:21:15OK, Justin, here we go.
0:21:20 > 0:21:23Instant, it's an instant, the heat through the glass.
0:21:25 > 0:21:28Yeah. My heart rate's definitely up.
0:21:29 > 0:21:34'The scenario Justin is simulating now is stage one of a burn-over,
0:21:34 > 0:21:37'when flames are approaching the truck.'
0:21:37 > 0:21:40So we're seeing quite a filtered amount of heat coming through,
0:21:40 > 0:21:43- so that's getting about half a kilowatt...- OK.
0:21:43 > 0:21:45..and we've got about 2.5 outside.
0:21:45 > 0:21:48- Right.- So this is sort of, um, already significantly hotter
0:21:48 > 0:21:52- than a hot sunny day.- Yeah. - But, but tolerable.
0:21:52 > 0:21:56Tolerable, yeah. I mean, it is like standing on Bonfire Night -
0:21:56 > 0:21:59it's like standing, you know, kind of close enough but thinking,
0:21:59 > 0:22:02"Mm, once I've got my baked potato I might take a step back."
0:22:02 > 0:22:05That's right. Feel like going up a notch?
0:22:05 > 0:22:07Yeah, go on, then.
0:22:07 > 0:22:11- OK, so bring it up to the next level, Martin.- OK.
0:22:18 > 0:22:21- OK, that's now feeling... - Now, now it's building, yeah.
0:22:21 > 0:22:23Really... I'm, I'm kind of...
0:22:23 > 0:22:28I can feel myself kind of just leaning away from the window.
0:22:28 > 0:22:32Definitely, even just a few centimetres makes a difference.
0:22:32 > 0:22:34We can already smell a little bit here.
0:22:34 > 0:22:36Oh, look, and actually it's starting to smoke.
0:22:36 > 0:22:39- What is smoking?- It's slightly cloudy inside the truck.
0:22:39 > 0:22:42So I'd say the plastic elements on the outside of the truck
0:22:42 > 0:22:44are starting to be a bit, um...
0:22:44 > 0:22:46Ooh, yeah, I can see...
0:22:46 > 0:22:48Yeah. You want to briefly go up a notch just before
0:22:48 > 0:22:51the truck gets a little bit too hot and burns?!
0:22:51 > 0:22:53- OK!- OK, go up one more notch.
0:22:53 > 0:22:55OK.
0:22:56 > 0:23:01OK, so we're now at... Oh, wow.
0:23:01 > 0:23:05- So...- OK, so the outside radiant heat is five and a half now,
0:23:05 > 0:23:08- inside...- So you'd now be feeling quite a lot of pain
0:23:08 > 0:23:11- potentially on your skin. - It's... You can't actually...
0:23:11 > 0:23:13We've pretty much got two kilowatts on us now.
0:23:13 > 0:23:16OK, yeah, you can't actually turn and look at the...
0:23:16 > 0:23:18Looking at you, it's more comfortable.
0:23:18 > 0:23:20We're pretty much at the threshold,
0:23:20 > 0:23:22and now the smoke's getting a bit hard, yeah.
0:23:22 > 0:23:24- The smoke's quite hard. - OK, shut down.
0:23:25 > 0:23:28Because there's a fair bit of smoke coming in the cabin,
0:23:28 > 0:23:31- I'd say we're better off climbing out.- OK, OK.
0:23:33 > 0:23:36'This kind of testing is vital for offering fire-fighters
0:23:36 > 0:23:41'who use Cat 7s the best advice in the event of a burn-over.'
0:23:41 > 0:23:45If we hadn't got out when we did, what would've happened?
0:23:45 > 0:23:48- We could feel a tingle in our mouths...- Yeah.
0:23:48 > 0:23:49And it was like we were...
0:23:49 > 0:23:53We were 10 to 20 seconds away from that being really irritating.
0:23:53 > 0:23:57At about 30 seconds, our eyes would've been really sore,
0:23:57 > 0:24:00and, you know, we'd be feeling quite headachy, say, for a few hours
0:24:00 > 0:24:04after that exposure if we didn't get out exactly when we did.
0:24:04 > 0:24:05Right.
0:24:05 > 0:24:07'Although the smoke in the cab was unpleasant,
0:24:07 > 0:24:11'in a real fire at the same point, the radiant heat outside
0:24:11 > 0:24:13'would actually be far more deadly.
0:24:13 > 0:24:16'In a fire scenario like this one, fire-fighters are trained to
0:24:16 > 0:24:19'stay in the cab, close all windows and vents,
0:24:19 > 0:24:23'get low, and cover themselves with a woollen blanket.'
0:24:23 > 0:24:24OK, we're ready,
0:24:24 > 0:24:28we can bring on the pre-radiation burners on level one.
0:24:31 > 0:24:34'But the other aim of the research is to improve the design
0:24:34 > 0:24:37'of these trucks so they can keep their crews safe,
0:24:37 > 0:24:39'even when conditions get more extreme.
0:24:40 > 0:24:42'To demonstrate how this is done,
0:24:42 > 0:24:45'the Cat 7 will now be subjected to the second stage
0:24:45 > 0:24:48'of the burn-over, when the truck is engulfed in flames.
0:24:48 > 0:24:51'Rural Fire Service chief engineer Andrew
0:24:51 > 0:24:53'works closely with Justin.'
0:24:53 > 0:24:57We wouldn't expect anyone to survive what we're about to witness,
0:24:57 > 0:25:01so what we want to see from here is all the weak points, OK,
0:25:01 > 0:25:04any fallibilities within the cab, on the vehicle.
0:25:04 > 0:25:05Next level.
0:25:05 > 0:25:07We're just upping the level.
0:25:09 > 0:25:14The wheels are igniting. OK, so main burners on now.
0:25:16 > 0:25:18Oh, my goodness!
0:25:18 > 0:25:21So this is the main fire front now going to engulf,
0:25:21 > 0:25:24engulf this side of the vehicle.
0:25:32 > 0:25:34So we've just moved to the offside burners,
0:25:34 > 0:25:37so the fire front's actually burning over the truck now.
0:25:37 > 0:25:38OK, so this is, this is now replicating
0:25:38 > 0:25:41a fire doing a literal burn-over.
0:25:41 > 0:25:42- That's right. - Crossing over the truck.
0:25:42 > 0:25:44So it's as if you're on a track with fuel
0:25:44 > 0:25:46and trees built up on both sides,
0:25:46 > 0:25:49so the fire front actually moves fully over the top of the truck.
0:25:49 > 0:25:52It's plain to see the impact... BANG! KATE GASPS
0:25:52 > 0:25:54- Ah! Sorry! Ha-ha! - That, that'll be a tyre.
0:25:54 > 0:25:56- Yes, that's tyre number one. - That's a tyre!
0:25:58 > 0:26:00OK, we'll get suppression ready.
0:26:04 > 0:26:07'Tests like these identify where the key safety advances
0:26:07 > 0:26:08'need to be made.'
0:26:14 > 0:26:17Well, I'm not sure you're going to be able to use this one again,
0:26:17 > 0:26:19Andrew. Oof!
0:26:20 > 0:26:23- Wow, it's like a horror film, isn't it?- It is, isn't it?
0:26:23 > 0:26:26What chills me the most is that volunteer fire-fighters
0:26:26 > 0:26:28- are in these vehicles...- Yeah.
0:26:28 > 0:26:31..and um, we want to make sure that they never get into this situation.
0:26:31 > 0:26:34What were the obvious things that...
0:26:34 > 0:26:36You said, OK, there is serious room for improvement
0:26:36 > 0:26:38in this particular scenario.
0:26:38 > 0:26:42Yeah, it's the windows. As you saw, the windows are all gone.
0:26:42 > 0:26:46- Yeah.- Um, that allows too much flame, etc, to enter.
0:26:46 > 0:26:49The doors - where the flame impacts on the door, melts everything inside,
0:26:49 > 0:26:52and starts to put a lot of smoke inside the cab so you can't breathe.
0:26:52 > 0:26:57- Yeah.- The other thing is all of the rubbers and any fuel under the cab.
0:26:57 > 0:26:59So tyres, that kind of thing.
0:26:59 > 0:27:03Tyres, plastics, anything that will cause flame to propagate is
0:27:03 > 0:27:07a fuel which will then impact inside the cab.
0:27:07 > 0:27:09'This research is helping Andrew
0:27:09 > 0:27:13'and Justin create a new generation of trucks.'
0:27:14 > 0:27:18So if we look at the newer model,
0:27:18 > 0:27:22um, I mean, obviously, it's a much bigger vehicle altogether.
0:27:22 > 0:27:24Does size matter?
0:27:24 > 0:27:27Not when it comes to crew protection, Kate, no, it doesn't.
0:27:27 > 0:27:29Just to explain a couple of things that we've done on some of
0:27:29 > 0:27:32the weak points that we saw on the older vehicle compared to this one -
0:27:32 > 0:27:34we have a ring main at the top,
0:27:34 > 0:27:36and those sprays up the top there are actually
0:27:36 > 0:27:39shedding water down each window, so it keeps the glass very cool.
0:27:39 > 0:27:43We have another spray under here, the tyres will be wet
0:27:43 > 0:27:44and kept cool.
0:27:45 > 0:27:49We changed the plastics, and we changed these to metal,
0:27:49 > 0:27:51- all of that's metal. - Everything's metal?
0:27:51 > 0:27:54One more feature that we do on here, plastic door handles -
0:27:54 > 0:27:57this is all metal now, so we replaced that with metal as well.
0:27:57 > 0:27:58Ah.
0:27:58 > 0:28:02And I'm assuming the blinds inside the windows are not decorative.
0:28:03 > 0:28:05Oh, wow, OK.
0:28:05 > 0:28:07This is reflecting back the radiant heat
0:28:07 > 0:28:08away from the inside of the cab.
0:28:08 > 0:28:10Exactly.
0:28:10 > 0:28:13That in itself means that anyone trapped in a burn-over
0:28:13 > 0:28:17in this vehicle has every reason to survive.
0:28:17 > 0:28:21Well, they have a much greater chance of survivability
0:28:21 > 0:28:23- than what they do in any other vehicle.- Right.
0:28:24 > 0:28:28'These new trucks will themselves be tested in a continual process
0:28:28 > 0:28:30'to create ever-safer vehicles.'
0:28:35 > 0:28:39'Throughout any fire season, there are peaks and troughs of activity,
0:28:39 > 0:28:42'and the situation can vary in different parts of this vast state
0:28:42 > 0:28:45'according to the particular weather conditions.
0:28:47 > 0:28:50'Back at Bathurst, it's been much cooler in the past few days,
0:28:50 > 0:28:54'bringing rain that has helped keep the fires under control.
0:28:56 > 0:29:00'At the Wollemi, temperatures remain in the 30s. The fires there
0:29:00 > 0:29:04'have now burnt through 470 square kilometres of wilderness.
0:29:12 > 0:29:15'While the air team continue to drop water on the fire,
0:29:15 > 0:29:19'ground teams in the park are now employing the next step
0:29:19 > 0:29:22'in their fire-fighting strategy. It's called containment,
0:29:22 > 0:29:26'and it involves using bulldozers to clear vegetation
0:29:26 > 0:29:30'ahead of a fire to remove the fuel it needs to burn and spread.
0:29:30 > 0:29:33'I've joined John in the driving seat.'
0:29:34 > 0:29:36OK, are you right for this?
0:29:36 > 0:29:38Yeah. Good for it, you knock it down.
0:29:43 > 0:29:46- Takes it down like it was a matchstick!- Yeah.
0:29:50 > 0:29:54Ooh. The power of this machine!
0:29:56 > 0:29:57Does a good job for its size.
0:29:59 > 0:30:02- The thing is, you don't even feel it here in the cab, do you?- No.
0:30:02 > 0:30:05There's no pause, it just goes straight through and over.
0:30:08 > 0:30:11'Each fire-break is around three to five metres wide,
0:30:11 > 0:30:15'so as well as restricting the fire, they can also provide
0:30:15 > 0:30:17'an access road for fire trucks.
0:30:20 > 0:30:22'But making them isn't as easy as it looks.'
0:30:24 > 0:30:28Oh, my goodness. OK. Nice and calm.
0:30:29 > 0:30:31Now we're going to go forward.
0:30:31 > 0:30:32'I've been given one job.'
0:30:34 > 0:30:37Slowly, I'm engaging the boulder!
0:30:39 > 0:30:41Oh, dear.
0:30:41 > 0:30:43Maybe a bit too much of the road, I think.
0:30:44 > 0:30:48I'm determined to get this rock off, yes, it's going! It's going!
0:30:50 > 0:30:53I have sort of helped to clear the road,
0:30:53 > 0:30:55and made a bit of a mess at the same time.
0:30:55 > 0:30:58I think it's time I let the professional back in the cab.
0:31:03 > 0:31:04I probably have seen worse.
0:31:04 > 0:31:07- Have you? - I probably have, but I'm not sure!
0:31:08 > 0:31:10- I'm sorry. - Practice, practice, mate.
0:31:13 > 0:31:18What they're doing obviously isn't as sexy as fighting
0:31:18 > 0:31:22the fire from a helicopter or from the sky, but it's an essential
0:31:22 > 0:31:28part of preventing and stopping the fires that ravage these areas.
0:31:31 > 0:31:33And they can fight the fire on their terms.
0:31:36 > 0:31:39We captured the Rural Fire Service using this technique
0:31:39 > 0:31:42to great effect at a fire in a pine plantation.
0:31:44 > 0:31:47Using a combination of roads and containment lines, the crews
0:31:47 > 0:31:51managed to stop the blaze in its tracks, allowing them to put it out.
0:31:53 > 0:31:55Sometimes they'll allow contained wildfires
0:31:55 > 0:31:58to burn out naturally, or be extinguished by rain.
0:32:00 > 0:32:03But containment lines aren't only made with bulldozers.
0:32:08 > 0:32:11In the Wollemi, they're using what appears to be
0:32:11 > 0:32:15a paradoxical tactic to slow the progress of a wildfire.
0:32:15 > 0:32:18They're deliberately lighting fires in its path.
0:32:18 > 0:32:22It's a process called back burning, which is essentially
0:32:22 > 0:32:24fighting fire with fire.
0:32:31 > 0:32:34As the approaching fire front burns with greater ferocity,
0:32:34 > 0:32:37it creates a pressure system.
0:32:41 > 0:32:43The hot air rises,
0:32:43 > 0:32:46and the smaller, deliberately lit fires
0:32:46 > 0:32:50are pulled towards the fire front, burning everything in their way.
0:32:51 > 0:32:55The process removes the fuel from the oncoming path of the fire...
0:32:56 > 0:32:59..and increases the size of the fire-break ahead.
0:33:01 > 0:33:05It's basically using a smaller fire to deprive a bigger fire of fuel.
0:33:08 > 0:33:11These containment techniques, along with dropping temperatures
0:33:11 > 0:33:14in New South Wales, mean that as we reach the last few days
0:33:14 > 0:33:16of our time here, the number of active fires
0:33:16 > 0:33:19has dropped from 106 to 42.
0:33:24 > 0:33:28But in the neighbouring state of Victoria, the weather is hotting up.
0:33:28 > 0:33:30I've travelled to Marlo Airbase,
0:33:30 > 0:33:33south of the Snowy River National Park.
0:33:35 > 0:33:38In this remote area, they're starting deliberate fires
0:33:38 > 0:33:42from helicopters to ensure bushfires currently under control
0:33:42 > 0:33:45don't take off again as the mercury rises.
0:33:46 > 0:33:48Mike Irvine is the team's leader.
0:33:48 > 0:33:50What we've had is quite a large fire.
0:33:50 > 0:33:53There's not a lot of activity out there now in terms of flames,
0:33:53 > 0:33:56but what it's left is a big unburnt patch in the middle.
0:33:56 > 0:33:59If that really gets cranking
0:33:59 > 0:34:02in the hotter weather, that can send up a lot of smoke,
0:34:02 > 0:34:05and also embers, which can spot outside the original fire,
0:34:05 > 0:34:09and then start a new fire or make the original fire bigger.
0:34:09 > 0:34:12So we drop incendiary balls from the helicopter
0:34:12 > 0:34:15to light up that unburnt area while the conditions are good
0:34:15 > 0:34:19- and not too extreme.- Can we go and see what they're doing?
0:34:19 > 0:34:20Yeah, I'll show you, come over.
0:34:20 > 0:34:24Hey, you guys, can you just pass me one of the balls? Thanks, Phil.
0:34:24 > 0:34:26So, they're like little ping pong balls, you can have a look.
0:34:26 > 0:34:29So it's got potassium permanganate powder inside,
0:34:29 > 0:34:34- and then this machine behind us here, it's got glycol.- Right.
0:34:34 > 0:34:38Which is antifreeze you use in your car, and there's a needle
0:34:38 > 0:34:41inside there, so the balls drop into a chute one at a time,
0:34:41 > 0:34:44they're injected with glycol, and then they'll drop out
0:34:44 > 0:34:47- the tube down the bottom there. - Oh, this one just down here, yeah.
0:34:47 > 0:34:51That's right, and then within 20 or 30 seconds, that'll ignite.
0:34:51 > 0:34:53And if it lands in some fuel, which is quite likely
0:34:53 > 0:34:56- where we're going today...- So leaf litter or something like that?
0:34:56 > 0:34:57Yeah, leaves and sticks
0:34:57 > 0:34:59and that, it will actually start a little fire.
0:34:59 > 0:35:01Thanks, guys, we'll crank it up.
0:35:01 > 0:35:04- OK, Phil. Good? - All right, yeah, all right. Go.
0:35:06 > 0:35:08'The machine can fire as many as 90 balls in one minute,
0:35:08 > 0:35:12'but a handful is enough to show how they work.'
0:35:22 > 0:35:25The wire's on the top so they don't fly out and...
0:35:25 > 0:35:27- BALL HISSES - Woo!
0:35:27 > 0:35:29..yeah, they don't shoot up in the air and sparks and that,
0:35:29 > 0:35:32- but they do a great job on the ground.- Yeah.
0:35:32 > 0:35:35'When the chemicals within the ping pong ball combine,
0:35:35 > 0:35:38'they prompt a thermal reaction which leads to ignition.
0:35:38 > 0:35:41'Key to using the incendiaries properly is ensuring
0:35:41 > 0:35:42'they ignite at the right moment.'
0:35:42 > 0:35:44I can see how they're effective.
0:35:44 > 0:35:47So that was about 23 seconds.
0:35:47 > 0:35:49Between 20 and 30 seconds is quite good,
0:35:49 > 0:35:51it gives them plenty of time to clear the helicopter
0:35:51 > 0:35:53and actually be on the ground when they catch on fire.
0:35:53 > 0:35:55And how accurate can you be?
0:35:55 > 0:35:57How do you know that you're not accidentally going to
0:35:57 > 0:36:00set off a fire in an area that you absolutely don't want to burn?
0:36:00 > 0:36:03- We're very low, just above the tree tops.- OK.
0:36:03 > 0:36:06And the turbulence from the helicopter is pushing
0:36:06 > 0:36:09straight down, so they're not really affected too much by the helicopter.
0:36:09 > 0:36:11If we did a sharp turn,
0:36:11 > 0:36:13it might shoot one out to the side a little bit,
0:36:13 > 0:36:17but generally they'll drop straight down and where we want them, so...
0:36:19 > 0:36:21'We're heading up to see the effect of the incendiaries
0:36:21 > 0:36:23'they dropped this morning.'
0:36:23 > 0:36:27- OK, everyone good to go? - Yep.- Yeah.
0:36:33 > 0:36:36So, where we're heading to you can see the fire
0:36:36 > 0:36:38off in the distance straight ahead.
0:36:38 > 0:36:41- We'll go and show you what we've been up to.- Great.
0:36:43 > 0:36:46Suddenly you can start to smell the smoke.
0:36:46 > 0:36:49We normally start off with just a little bit and then build up,
0:36:49 > 0:36:53- cos obviously you can't take fire out once you've put it in...- Yeah.
0:36:53 > 0:36:56..but you can always add a little bit more if you need.
0:36:56 > 0:36:58Wow, it's getting very smoky up ahead.
0:36:58 > 0:37:02- So that stuff in there is what we lit two days ago.- Yeah.
0:37:02 > 0:37:05And the stuff out ahead of us, a bit more up to the left there,
0:37:05 > 0:37:09is what we lit just before, and it's burning quite well, so...
0:37:09 > 0:37:11It's really interesting looking down on them,
0:37:11 > 0:37:15and it is following a very neat line.
0:37:16 > 0:37:19What we do is light it up the top and let it just run down slowly,
0:37:19 > 0:37:22so it doesn't do too much, too much damage,
0:37:22 > 0:37:25but still burns out underneath, which is what we want.
0:37:25 > 0:37:28We want it to be nice and safe, so nothing's going to spring up
0:37:28 > 0:37:29and surprise us.
0:37:30 > 0:37:33'Mike and his team are creating low-intensity fires
0:37:33 > 0:37:36'before temperatures rise to burn away the leaf litter
0:37:36 > 0:37:40'on the floor, removing the fuel source for any future ignition.
0:37:41 > 0:37:43'This incendiary process is a simple
0:37:43 > 0:37:47'but effective way of safely burning vast swathes of land.'
0:37:51 > 0:37:55How many balls did you, did you drop this morning?
0:37:55 > 0:37:58- Um, we put about 140 balls into that area...- Right.
0:37:58 > 0:38:01..and the area's probably about three or four kilometres
0:38:01 > 0:38:03by three or four kilometres,
0:38:03 > 0:38:07so that's like 140 little fires along the top of the ridge, and as
0:38:07 > 0:38:11you can see they're starting to join up now and do a really good job.
0:38:11 > 0:38:14So it looks quite hot on top of the ridges,
0:38:14 > 0:38:15but once the ridges are burnt out,
0:38:15 > 0:38:18they'll start to back down the ridges towards the gulleys
0:38:18 > 0:38:21a little bit more gently, which is exactly what we want.
0:38:21 > 0:38:23So you're pleased that today went well?
0:38:23 > 0:38:25Yeah, very pleased. It's really good.
0:38:27 > 0:38:31'While scientists and fire-fighters are constantly evolving
0:38:31 > 0:38:35'better methods to control and contain wildfires,
0:38:35 > 0:38:37'there's one fire that is so formidable
0:38:37 > 0:38:40'it simply can't be contained.'
0:38:43 > 0:38:46In January 2003, a massive fire hit Canberra,
0:38:46 > 0:38:49Australia's capital city,
0:38:49 > 0:38:55engulfing 2,600 square kilometres in a single day.
0:38:55 > 0:38:59It was a huge fire, but what made it unusual was that it created
0:38:59 > 0:39:01a massive spinning vortex of flame.
0:39:02 > 0:39:06This phenomenon has been described as a giant fire whirl
0:39:06 > 0:39:08or fire tornado.
0:39:08 > 0:39:12Local residents Gary and Trish witnessed it first-hand.
0:39:12 > 0:39:15The sky was blood-red, and then it just started...
0:39:15 > 0:39:19just this big, swirling type black smoke
0:39:19 > 0:39:22just appeared over there.
0:39:22 > 0:39:26Shortly after that, I saw one of those big gum trees
0:39:26 > 0:39:28at the top of the mountain snap, and that went
0:39:28 > 0:39:30about 50m up in the air across the mountain
0:39:30 > 0:39:33and then disappeared out the back there somewhere.
0:39:33 > 0:39:35So it was behaving exactly like a tornado,
0:39:35 > 0:39:38it was lifting stuff up and chucking it in the air?
0:39:38 > 0:39:41Yeah. Then all of a sudden we saw that huge fireball,
0:39:41 > 0:39:43it was like an explosion of fire.
0:39:45 > 0:39:46Get in mate, quick steps.
0:39:48 > 0:39:51The Canberra tornado proved that fires are capable of creating
0:39:51 > 0:39:55their own extreme weather systems as dangerous as the fire itself.
0:39:55 > 0:40:00Exactly what leads to this kind of event is debated by scientists.
0:40:03 > 0:40:06But fire behaviour expert Jason Forthofer
0:40:06 > 0:40:08has developed an ingenious method
0:40:08 > 0:40:11to demonstrate one way they can be caused.
0:40:12 > 0:40:15We lit these five different fires
0:40:15 > 0:40:19and each fire is trying to suck air into the base of it
0:40:19 > 0:40:22to replace the hot air that's rising.
0:40:22 > 0:40:24And the only air that it can really draw in well
0:40:24 > 0:40:27is through these gaps between the fires.
0:40:27 > 0:40:29And by drawing air in just through those gaps,
0:40:29 > 0:40:31that causes the rotating motion.
0:40:31 > 0:40:34And then that rotating motion is stretched
0:40:34 > 0:40:37and causes this fire whirl that spins up to a high velocity.
0:40:40 > 0:40:44To grow, fires need a constant supply of oxygen
0:40:44 > 0:40:47and they do this by sucking in air at their base.
0:40:50 > 0:40:51Fire whirls can occur
0:40:51 > 0:40:54when a number of fires burn in close proximity
0:40:54 > 0:40:58and compete for air, creating a circular airflow.
0:40:58 > 0:41:00This can happen in wildfires
0:41:00 > 0:41:03when spotting fires, caused by flying embers,
0:41:03 > 0:41:06ignite around the main fire front.
0:41:07 > 0:41:09Using high-speed cameras
0:41:09 > 0:41:12we can see how the flame behaves in intricate detail.
0:41:13 > 0:41:16Slowed right down to 1/20 of normal speed
0:41:16 > 0:41:19you can see the central flame spin
0:41:19 > 0:41:21and then stretch vertically.
0:41:21 > 0:41:25Rising hot air acts on that rotating motion.
0:41:25 > 0:41:27It spins up into a really tight whirl.
0:41:28 > 0:41:29In the real world
0:41:29 > 0:41:33these fire whirls can get up to be 100mph or more.
0:41:33 > 0:41:35They've been known to tear roofs off houses
0:41:35 > 0:41:36and tip cars over.
0:41:38 > 0:41:41Subsequent analysis of the Canberra tornado
0:41:41 > 0:41:44revealed that the fire created its own superheated winds
0:41:44 > 0:41:48travelling at 250kph.
0:41:49 > 0:41:53Given the unstoppable power of tornadoes like this
0:41:53 > 0:41:58Jason's research is focused on providing an early warning system.
0:41:58 > 0:41:59Our hope with our research
0:41:59 > 0:42:02is that we can give fire-fighters insight
0:42:02 > 0:42:04into likely locations where they may form.
0:42:04 > 0:42:07And then also to be aware when they do form
0:42:07 > 0:42:09the kind of damage that they can do.
0:42:16 > 0:42:18For Canberra residents Gary and Trish
0:42:18 > 0:42:21it's an experience they're unlikely to forget.
0:42:21 > 0:42:22It just happened so quick.
0:42:22 > 0:42:24Dropped everything, ran in the house...
0:42:24 > 0:42:28- 30 seconds later, boom, it just... - And it just hit.- ..hit.
0:42:28 > 0:42:31And just that noise, the incredible jet engine noise,
0:42:31 > 0:42:33was just roaring out.
0:42:35 > 0:42:39If that fireball had been...
0:42:39 > 0:42:42a couple of metres, or whatever, more towards the house
0:42:42 > 0:42:45I'd...yeah, I would hate to think what happened.
0:42:48 > 0:42:51What eventually halted the tornado is uncertain.
0:42:51 > 0:42:53But it lasted for an hour,
0:42:53 > 0:42:56travelling 40km before finally dying out.
0:43:00 > 0:43:02Back in Bathurst, New South Wales,
0:43:02 > 0:43:05the recent rainfall has helped to suppress the flames
0:43:05 > 0:43:07and wind speeds have dropped,
0:43:07 > 0:43:10allowing fire-fighters to get the upper hand.
0:43:10 > 0:43:12The fires are now under control.
0:43:12 > 0:43:13While the conditions are calmer
0:43:13 > 0:43:17there's a brief opportunity to enter the scorched fire grounds
0:43:17 > 0:43:20and make sure any remaining hot spots
0:43:20 > 0:43:21are completely extinguished.
0:43:21 > 0:43:24I'm joining the mopping-up operation.
0:43:24 > 0:43:27At the moment we've got mopping-up operations
0:43:27 > 0:43:30which is basically going in, hitting any hot spots,
0:43:30 > 0:43:33any bits of fire that may be underground, in tree stumps,
0:43:33 > 0:43:35in trunks of trees, etc,
0:43:35 > 0:43:39and making sure that they're completely extinguished.
0:43:39 > 0:43:41The crews out there today will actually be off the trucks,
0:43:41 > 0:43:43walking through the burnt ground,
0:43:43 > 0:43:46- feeling for any heat that's coming up out of the ground.- Wow.
0:43:46 > 0:43:49Is this a dangerous operation?
0:43:49 > 0:43:52Any operation, any time, is always dangerous.
0:43:52 > 0:43:55We've got falling trees. Especially with a bit of wind,
0:43:55 > 0:43:57trees that are fire-damaged can fall at any time.
0:43:57 > 0:44:00The bush is dry so if anything starts from an ember
0:44:00 > 0:44:02it's going to spread fairly quickly.
0:44:02 > 0:44:05So everyone has to be alert
0:44:05 > 0:44:07- that fire could reignite at any time?- Yeah.
0:44:07 > 0:44:10- Well, we'll go and see what they do. - Yes, let's go.
0:44:12 > 0:44:16Crews work eight-hour shifts, covering the ground systematically.
0:44:16 > 0:44:18You need eagle eyes
0:44:18 > 0:44:21and it also helps to have an infrared camera like Chris's.
0:44:22 > 0:44:26Kate, perhaps just have a look at this one.
0:44:26 > 0:44:27Got a bit of a hot spot here.
0:44:30 > 0:44:31- Oh, my goodness, yeah!- Yeah.
0:44:31 > 0:44:35- Wow! Over 300 degrees!- Yeah, we cracked the 300-degree mark.
0:44:35 > 0:44:37And you'd never...I mean, I was heading down
0:44:37 > 0:44:39for the very obvious hot spots, the smoking areas.
0:44:39 > 0:44:42- I would never ever have considered this.- No.
0:44:42 > 0:44:47The FLIR cameras were first used by the Rural Fire Service in 2008
0:44:47 > 0:44:50and are now indispensable to front-line fire detection.
0:44:50 > 0:44:54It really is helping us do things that you ordinarily might not see.
0:44:54 > 0:44:56And if you did miss things like this,
0:44:56 > 0:44:58how dangerous are they?
0:44:58 > 0:45:00Well, it depends a bit on the weather conditions.
0:45:00 > 0:45:02But this is a risky slope
0:45:02 > 0:45:06because the unburnt is on the upslope side
0:45:06 > 0:45:11and we've got quite a bit of leaf-fall which will happen.
0:45:11 > 0:45:13- So you need to kind of nip this in the bud, basically...- Yes.
0:45:13 > 0:45:16..before it becomes another, as you say, flash point.
0:45:16 > 0:45:19So we'll expose it with a rake in a minute.
0:45:19 > 0:45:22- So you can do a bit of raking. - OK, yeah, put me to work.- OK!
0:45:22 > 0:45:23And then we'll bring the hose line down,
0:45:23 > 0:45:26- lay a bit of foam on it so we take the heat out of it.- Yeah.
0:45:26 > 0:45:29So you're exposing the fuel, removing the heat,
0:45:29 > 0:45:32- smothering it with a bit of foam.- OK.
0:45:32 > 0:45:36- So that's your heat triangle - fuel, heat, air.- Right.
0:45:36 > 0:45:39- Get rid of them.- So you've got rid of all those things.- Yeah.
0:45:39 > 0:45:43Right, OK, you'd better put me to work. Who's got a rake?
0:45:43 > 0:45:44A hot spot like this is formed
0:45:44 > 0:45:47when a fire has spread into the roots of a tree
0:45:47 > 0:45:49and continues to burn beneath the ground.
0:45:51 > 0:45:55So you're basically digging down into here,
0:45:55 > 0:45:57exposing the hotter stuff.
0:45:57 > 0:46:00You're starting to just see a little bit of smoke
0:46:00 > 0:46:03- actually coming up from there, aren't you, now?- Yeah,
0:46:03 > 0:46:06- Look at this, Chris.- Yeah.
0:46:06 > 0:46:08- It's already glowing.- Yeah, yeah.
0:46:08 > 0:46:11That's certainly gone into an active flame stage
0:46:11 > 0:46:14- because it's exposed to the air. - Right.
0:46:14 > 0:46:16- A little bit of air movement upslope...- Yeah.
0:46:16 > 0:46:17..and away it goes.
0:46:19 > 0:46:23- Wow, it does boil up, doesn't it? - Yeah. That's cos it's...
0:46:23 > 0:46:25- It's like a kind of frothing cappuccino.- ..taken the heat out.
0:46:25 > 0:46:27Sometimes we've got to be a bit cautious
0:46:27 > 0:46:29with how much water we use because, you know,
0:46:29 > 0:46:31we mightn't be able to quickly refill
0:46:31 > 0:46:34so we're having some economy with water.
0:46:34 > 0:46:37- If you rake it around a little bit now, while I spray it.- OK.
0:46:37 > 0:46:39- So what do you want me to do? - Just dig it out.
0:46:39 > 0:46:42Do you want me to push it back or dig it out?
0:46:42 > 0:46:43And is this foam already...?
0:46:43 > 0:46:45This is foam coming out, now.
0:46:45 > 0:46:48So you're mixing the foam in automatically, kind of thing?
0:46:48 > 0:46:50Yeah, up at the pump.
0:46:50 > 0:46:54And the foam basically then keeps it sort of airtight, seals off?
0:46:54 > 0:46:59- It'll just sit there for hours. - Right.
0:46:59 > 0:47:01That's still smoking a bit, there.
0:47:06 > 0:47:08- No red...- Probably nothing much over 30 there, now.
0:47:08 > 0:47:10Brilliant, OK.
0:47:10 > 0:47:13So one down, how many more do you reckon there are to go?
0:47:13 > 0:47:15Well, that is the question!
0:47:15 > 0:47:19Are you good at picking Lotto coupons, too?
0:47:22 > 0:47:23Yeah, this is a hot one.
0:47:25 > 0:47:27The departing fire leaves danger
0:47:27 > 0:47:29not only beneath the ground but above it, too.
0:47:30 > 0:47:33If you look up there at the canopy,
0:47:33 > 0:47:37this looks like a perfectly healthy eucalyptus tree,
0:47:37 > 0:47:39but if you come down to my level
0:47:39 > 0:47:42and you look down into the roots
0:47:42 > 0:47:46you can see that actually it is glowing.
0:47:46 > 0:47:48And if I use the thermal imaging camera,
0:47:48 > 0:47:50look at that!
0:47:50 > 0:47:54It is upwards of...
0:47:56 > 0:47:57..600 degrees in there.
0:47:59 > 0:48:03This is what the RFS charmingly called a widow-maker.
0:48:03 > 0:48:08And what happens, or what can happen, with these trees
0:48:08 > 0:48:11is that they look perfectly healthy
0:48:11 > 0:48:13but one big gust of wind...
0:48:13 > 0:48:17and because its roots have basically been burnt out
0:48:17 > 0:48:21it can just tumble like a matchstick.
0:48:21 > 0:48:24A very, very easy thing to fall on someone's head.
0:48:24 > 0:48:28So you can see why the widow-maker trees are the things
0:48:28 > 0:48:30that the fire-fighters fear the most.
0:48:32 > 0:48:35Chris and his colleagues continue to work until nightfall
0:48:35 > 0:48:37and they'll be back again tomorrow.
0:48:40 > 0:48:43It's incredible to imagine that across New South Wales
0:48:43 > 0:48:46they have to repeat this process with thousands upon thousands
0:48:46 > 0:48:48of individual fires throughout the season.
0:48:59 > 0:49:02Every year, on average, wildfires burn through
0:49:02 > 0:49:05half a million square kilometres of Australia.
0:49:07 > 0:49:11And because wildfires have been part of the natural cycle here
0:49:11 > 0:49:12for millions of years,
0:49:12 > 0:49:16the native plants have had to evolve extraordinary adaptations
0:49:16 > 0:49:19to survive being repeatedly scorched.
0:49:24 > 0:49:28One of Australia's leading ecologists, Tina Bell,
0:49:28 > 0:49:31studies the regeneration of forests after wildfires.
0:49:33 > 0:49:36I'm meeting her in the Blue Mountains National Park,
0:49:36 > 0:49:38just outside the town of Winmalee,
0:49:38 > 0:49:40to see exactly what happens.
0:49:42 > 0:49:46You're an ecologist, I would've thought that fire
0:49:46 > 0:49:49would be a kind of nightmare for you.
0:49:49 > 0:49:52No, no, it's the best thing that can happen.
0:49:52 > 0:49:56It just shows you how dynamic a forest can be.
0:49:56 > 0:50:00In one way or another, every species in this forest
0:50:00 > 0:50:02is dependent on fire for regeneration,
0:50:02 > 0:50:04either from a new individual as a seed
0:50:04 > 0:50:07or new sprouts from a tree that looked dead before.
0:50:09 > 0:50:12Only three months ago fire ripped through here,
0:50:12 > 0:50:14burning everything in its way.
0:50:14 > 0:50:18If you'd come here the day after, it would've been just black.
0:50:18 > 0:50:21So all this greenery that we're seeing now
0:50:21 > 0:50:24coming out of the ground or sprouting out of the trees
0:50:24 > 0:50:27- has happened since the fire? - Absolutely.
0:50:27 > 0:50:30You know, you can see some green within a week after the fire.
0:50:30 > 0:50:33There are flowers, Tina!
0:50:33 > 0:50:35Yes, and that's one of the features
0:50:35 > 0:50:38that this plant uses to survive in this area.
0:50:38 > 0:50:40You know, grow fast after a fire,
0:50:40 > 0:50:42be one of the first flowers around
0:50:42 > 0:50:44and you've got the best chance of being pollinated.
0:50:44 > 0:50:47There's nothing else for insects to feed on here.
0:50:47 > 0:50:50What form would it have been effectively dormant in?
0:50:50 > 0:50:54What this plant uses is an underground tuber.
0:50:54 > 0:50:56And just being a couple of centimetres below the ground
0:50:56 > 0:50:59is enough to protect it from the heat.
0:50:59 > 0:51:02The blue Dampiera is one of the smallest benefactors
0:51:02 > 0:51:04from the fire in the forest.
0:51:04 > 0:51:06And this is one of the biggest.
0:51:07 > 0:51:09Oh, my goodness, what a magnificent tree.
0:51:09 > 0:51:12- Isn't it?- What is it?
0:51:12 > 0:51:14This is a Sydney red gum,
0:51:14 > 0:51:16one of the iconic trees for this area.
0:51:16 > 0:51:19- I can see why it's called red gum. - Yes, look at that!
0:51:19 > 0:51:21Isn't that just beautiful?
0:51:21 > 0:51:24Some damage has been done during the fire
0:51:24 > 0:51:26and exposed the tissue underneath.
0:51:26 > 0:51:28And it's almost acting like blood coagulating.
0:51:28 > 0:51:31- It's...- And clots, so it's like a scab almost?
0:51:31 > 0:51:33- Yeah. Yes, yes, it is. - To heal the tree.- It is indeed.
0:51:33 > 0:51:36And it's got its own antiseptic properties as well.
0:51:36 > 0:51:37- Really?- Yeah.
0:51:37 > 0:51:38Isn't that amazing?
0:51:38 > 0:51:40And the bark...?
0:51:40 > 0:51:42- You can see here it's black. So it was burnt...- Yeah.
0:51:42 > 0:51:44- And since then it's fallen off.- Yeah.
0:51:44 > 0:51:48The heat was enough to kill that living tissue
0:51:48 > 0:51:49and now it's fallen away.
0:51:49 > 0:51:53And the tree underneath it is going to be healthy because it,
0:51:53 > 0:51:56- what, this bit wasn't burnt? - That's exactly right.
0:51:57 > 0:52:00But whilst nature has adapted to tolerate fire,
0:52:00 > 0:52:04certain species actually need fire to survive.
0:52:04 > 0:52:07- This is a Banksia.- A Banksia?
0:52:07 > 0:52:10Yeah, so it's a common species around this area.
0:52:10 > 0:52:12And what this is is its seed pod
0:52:12 > 0:52:15and the seeds are protected from the fire in there.
0:52:15 > 0:52:19Normally they're closed up and this is covered in fur
0:52:19 > 0:52:22and it looks like a mouse with a bad hair day!
0:52:22 > 0:52:25When the fire comes through it burns it off, it kills this branch,
0:52:25 > 0:52:28and that's enough to open up these follicles here
0:52:28 > 0:52:30and the seed can pop out.
0:52:30 > 0:52:32If you look around you'll be able to find a seedling or so.
0:52:32 > 0:52:34- There.- That's the one there.
0:52:34 > 0:52:37It's come straight from the parent tree onto the ground
0:52:37 > 0:52:38and germinated.
0:52:38 > 0:52:42So this whole species of plant
0:52:42 > 0:52:46is totally dependent on fire to be able to regenerate?
0:52:46 > 0:52:49Yes. Yes, that's the only way
0:52:49 > 0:52:52we'll get new plants of this particular tree.
0:52:54 > 0:52:57The ability of plants to evolve in this way provides
0:52:57 > 0:53:00an astonishing illustration of just how fundamentally
0:53:00 > 0:53:04wildfire and the Australian landscape are linked.
0:53:04 > 0:53:08And in the same way that plants have developed ways of living with fire,
0:53:08 > 0:53:10so the people who inhabit this land
0:53:10 > 0:53:14must continually develop more sophisticated technology
0:53:14 > 0:53:16to allow them to live with it, too.
0:53:19 > 0:53:22As our time in New South Wales comes to an end
0:53:22 > 0:53:26I'm keen to know what the future of fire-fighting holds.
0:53:26 > 0:53:29To find out I'm meeting Professor Kevin Tolhurst,
0:53:29 > 0:53:31from the University of Melbourne,
0:53:31 > 0:53:33an expert in fire ecology and management,
0:53:33 > 0:53:36who's spent his career studying fire behaviour.
0:53:36 > 0:53:38He's created what could become
0:53:38 > 0:53:41the future of wildfire prediction across the world.
0:53:41 > 0:53:44It's known as Phoenix Rapidfire.
0:53:44 > 0:53:48We've got a huge screen in front of us, but Kevin, can I ask,
0:53:48 > 0:53:51what is Phoenix Rapidfire?
0:53:51 > 0:53:54Phoenix Rapidfire is a computer programme
0:53:54 > 0:53:57that predicts the spread and the nature of fire.
0:53:57 > 0:53:59So for every point across the landscape
0:53:59 > 0:54:01it'll tell you how high the flames are,
0:54:01 > 0:54:02how fast the fire's moving,
0:54:02 > 0:54:04how many embers are being produced,
0:54:04 > 0:54:08and it gives you a spatial and temporal description of fire
0:54:08 > 0:54:10across the landscape.
0:54:10 > 0:54:11So you're able to predict
0:54:11 > 0:54:15what I would think of as being unpredictable - a wildfire?
0:54:15 > 0:54:17But fires aren't unpredictable,
0:54:17 > 0:54:19fires still follow the laws of science.
0:54:19 > 0:54:23So whether it's physics or chemistry that's involved in fire behaviour,
0:54:23 > 0:54:26you just need to understand what those relationships are
0:54:26 > 0:54:28and how they interact.
0:54:28 > 0:54:30Is there a button you can press to start it up
0:54:30 > 0:54:31so we can see what's going to happen?
0:54:31 > 0:54:33Well, we can run the model.
0:54:33 > 0:54:35So what we're seeing displayed here
0:54:35 > 0:54:37is how the fire is spreading across the landscape.
0:54:37 > 0:54:40To model a fire in real-time
0:54:40 > 0:54:43all Kevin needs to do is enter the location of the fire
0:54:43 > 0:54:45and the time it started.
0:54:45 > 0:54:49The computer then cross-references this info with a live weather feed
0:54:49 > 0:54:53and stored data about topography, fire history and vegetation
0:54:53 > 0:54:55to map the fire.
0:54:55 > 0:54:58So the computer has just churned the data
0:54:58 > 0:55:01and now it's mapping it.
0:55:01 > 0:55:03The different colours are showing the activity of the fire.
0:55:03 > 0:55:05So the purple areas are showing
0:55:05 > 0:55:07where the fire has self-extinguished, gone out.
0:55:07 > 0:55:12Yellow/brown colours are showing the relative flame height.
0:55:12 > 0:55:15What makes the model truly ground-breaking
0:55:15 > 0:55:19is that it can also predict how fire will spread up to six hours ahead.
0:55:19 > 0:55:21Because of the strong southerly wind,
0:55:21 > 0:55:24a significant growth of the fire to the north.
0:55:24 > 0:55:26Knowing that this is the potential of the fire,
0:55:26 > 0:55:29you would then allocate your resources in such a way
0:55:29 > 0:55:32to make sure that the area of greatest impact is prevented.
0:55:32 > 0:55:34So this is important intelligence
0:55:34 > 0:55:37or important information for planning by the fire agencies.
0:55:37 > 0:55:39And if you can't stop it then it's really important
0:55:39 > 0:55:42to make sure you advise the community
0:55:42 > 0:55:44what they're likely to be impacted by
0:55:44 > 0:55:48so that they can take appropriate action to defend themselves.
0:55:48 > 0:55:53Phoenix Rapidfire is able to predict fire behaviour with 90% accuracy
0:55:53 > 0:55:55and that accuracy means
0:55:55 > 0:55:58that it's now being used at the Rural Fire Service HQ.
0:56:00 > 0:56:02On the main central command board
0:56:02 > 0:56:04is an ominous column entitled "Time to Impact."
0:56:06 > 0:56:10This is the time that remains before a wildfire will hit a community.
0:56:11 > 0:56:13As Kevin's model proves its worth here
0:56:13 > 0:56:15it's gradually being introduced
0:56:15 > 0:56:18in other wildfire-affected parts of the world.
0:56:19 > 0:56:23With more and more houses being built on land prone to fires,
0:56:23 > 0:56:26tools like this will help to protect them.
0:56:26 > 0:56:28And there's another reason
0:56:28 > 0:56:31why all of the fire-fighting technology we've seen in Australia
0:56:31 > 0:56:32is becoming more vital.
0:56:33 > 0:56:36There's a lot of concern in Australia
0:56:36 > 0:56:39that our climate is changing.
0:56:39 > 0:56:44Are you seeing any evidence of that in the fires that you study?
0:56:44 > 0:56:46The climate change that we're seeing, really,
0:56:46 > 0:56:49is accentuating the extremes of conditions.
0:56:49 > 0:56:52And what we can see in modelling and fire behaviour
0:56:52 > 0:56:56is it's the extreme conditions that drive these large fire events.
0:56:56 > 0:56:58And because the frequency is increasing,
0:56:58 > 0:57:01therefore we're seeing more severe fires.
0:57:01 > 0:57:04And as a consequence of that we're going to basically find
0:57:04 > 0:57:08that people will not only see a bushfire once in their lifetime,
0:57:08 > 0:57:11they may see it two or three times in their lifetime.
0:57:11 > 0:57:13So in the past we've been very quick
0:57:13 > 0:57:17at trying to rebuild a neighbourhood, rebuild a house,
0:57:17 > 0:57:20rebuild our lives in the same way as it was before
0:57:20 > 0:57:25to say "We can overcome this. We can rule over nature."
0:57:25 > 0:57:26But the reality is that
0:57:26 > 0:57:31with increasing severity of weather and associated fires
0:57:31 > 0:57:34that's going to be a folly.
0:57:34 > 0:57:39So we actually need to be even better prepared for fire
0:57:39 > 0:57:42because it's going to be a more regular occurrence.
0:57:48 > 0:57:51With fires expected to grow fiercer
0:57:51 > 0:57:53and the population of this fire-prone state
0:57:53 > 0:57:57predicted to grow by another million before 2020,
0:57:57 > 0:57:59the need to better understand wildfire
0:57:59 > 0:58:00and how to control it
0:58:00 > 0:58:02is ever more pressing.
0:58:07 > 0:58:10As we've seen, scientists are working with fire-fighters
0:58:10 > 0:58:13to make sure that everyone stays one step ahead of the flames.
0:58:13 > 0:58:15Our time in Australia is over,
0:58:15 > 0:58:18but the battle to protect this magnificent landscape,
0:58:18 > 0:58:22and the people who live here, against those wildfires will go on.