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00:16A freakish kind of weather event.
00:19We should not be.
00:21I'm checking right now.
00:23Is now striking again and again.
00:26People were panicking, running, taking cover.
00:30Intense.
00:31Batten down the hatches for the potential for straight line wind gusts.
00:35In excess of 75 miles an hour.
00:39Highly localized.
00:41That thing just collapsed right on those mountains.
00:43And all that air is just exploding.
00:47And devastating.
00:51It sucked windows out.
00:53There was glass everywhere.
00:56They fall from the sky without warning.
01:02Explosions of wind and water so violent.
01:05They can flatten homes in seconds.
01:09They're known as rain bombs.
01:12And they're getting stronger.
01:14The damage each year just continues to pile up and up and up.
01:19Now researchers are attempting to understand these destructive weather events.
01:24In some cases it can look like a bomb went off.
01:28Trying to predict where they'll drop and when.
01:32It's not safe to be outside.
01:34We've got about 20 minutes until this severe storm passes through.
01:39Rain bombs.
01:41Right now.
01:43On Nova.
01:44on Nova.
01:45on Nova.
02:00on Nova.
02:07t
02:09August 2011, the Puckle Pop Music Festival, Belgium.
02:15Out of nowhere, the skies darken.
02:19As powerful winds gust at over 80 miles per hour.
02:28Stages collapse.
02:29Very quickly, within a couple of minutes, it became probably the heaviest rain I'd ever seen.
02:34Lauren Behan was 19 when she and her friends travelled from Ireland to Belgium for the festival.
02:42You couldn't see anything really.
02:44There was wind blowing debris.
02:47It was very much a case of feeling like we were trapped.
02:52For it to turn from such a sunny, cloudless day to something apocalyptic in the space of 20 minutes is
02:59frightening.
03:00It's like something from a disaster movie.
03:03140 people are injured, and five festival-goers lose their lives.
03:13August 2024, a superyacht called the Basian sinks off the coast of Sicily.
03:21CCTV from the shore that night catches the vessel's mast, lights barely visible in the 100-mile-per-hour wind
03:28gusts and rain.
03:31It drags anchor, then capsizes.
03:36Divers recover seven bodies from the wreckage.
03:44July 2018.
03:47In heavy rain at Durango International Airport, Aeromexico Connect Flight 2431 is cleared for takeoff.
04:12The aircraft crashes back down to earth before it even clears the runway.
04:18Miraculously, there are no fatalities.
04:26Each of these events was caused by a mysterious weather phenomenon recognized only in the last 50 years.
04:35Each began with a thunderstorm, but what followed was much more violent and unexpected.
04:45Highly localized, sudden and extreme rainfall, and low-altitude, high-speed winds.
04:54They're nicknamed rain bombs, but scientists call them downbursts.
05:00So what are they, and what causes them?
05:18Mike Olbinski is one of the world's foremost thunderstorm photographers.
05:24After 15 years of chasing storms, he's mastered the art of being in exactly the right spot at the right
05:31time
05:31to photograph an elusive weather phenomenon.
05:35Rain bombs exploding from the sky.
05:40His images can help scientists understand how these weather systems form and how they detonate.
05:48We have an updraft going up right to our west.
05:52And then this big storm is forming right behind it, and I can see it on the horizon.
05:57So I think we need to get a little bit more west.
06:08Growing up in Phoenix, we used to watch lightning storms, you know, outside at night.
06:15I loved them, and I've always loved them, and I traced it back to seeing a lightning bolt strike behind
06:21my house.
06:22I still have this insane, vivid memory of it happening.
06:27Mike is on the hunt for rain bombs.
06:31These intense weather events are striking with greater strength than ever.
06:36To track one down, he first needs to find a developing thunderstorm.
06:44But what is the difference between a rain bomb and a run-of-the-mill thunderstorm?
06:51In a normal thunderstorm, you get heavy rainfall, lightning, and sometimes hail.
06:56And this can happen over hours.
07:00A thunderstorm can drop rain at about two inches per hour.
07:04A rain bomb can triple that rate.
07:09And in a rain bomb, the rain and hail aren't just falling to the ground.
07:15They're being thrown down by hurricane force vertical winds.
07:20What does a rain bomb look like?
07:22It looks like a massive volume of rain and cold air coming from cloud base to the surface.
07:38Across the planet, there are 2,000 electrical storms generating thunder and lightning at any given moment.
07:47Each one of them releases more energy over its lifetime than the 15 kiloton atomic bomb dropped on Hiroshima.
07:56Every rain bomb forms from a developing thunderstorm.
08:00But to understand how, we must first understand how clouds form.
08:11When sunlight hits the Earth, the surface heats up, and water from oceans, lakes, soils, and plants starts to evaporate,
08:20turning into water vapor.
08:24That water vapor, and the warm air around it, start to rise.
08:30As it starts to rise, it takes all of the water vapor near the surface of the Earth up into
08:37the atmosphere.
08:39As it lifts that up in the air, that parcel of air cools.
08:44The colder the parcel, the less able it is to carry around that water vapor, and so it forces it
08:52out into the formation of cloud droplets.
08:56Clouds form where the water vapor condenses into tiny water droplets, so small and light that they stay aloft instead
09:04of falling as rain.
09:07The altitude where this happens is called the cloud base.
09:12You see lots of little clouds developing, and they all have the same cloud base.
09:18So the cloud bases are actually occurring at the same temperature, and hence the same height.
09:29In Arizona, the summer monsoon season has arrived.
09:34It carries moist warm air from the Gulf of California, the perfect fuel for thunderstorms and rain bombs.
09:42We can feel it in the air, that it's really humid out, there's moisture, it's warm.
09:47So we've got the environment for storms to form.
09:51We're seeing these strong cauliflower kind of shapes at the top.
09:55When you're seeing that, you've got to imagine how intense that is to go from nothing to this sharply defined
10:03cloud.
10:04And then a couple of them get a little bigger, and then you get something like this where, boom, it
10:07erupts.
10:11If the conditions are right, these simple clouds can turn into thunderstorms.
10:17When you have these puffy, fluffy clouds that you see in the sky, there's some interesting things going on inside.
10:24Condensation is happening, and heat is actually being released as water vapor is changing to water.
10:31As the water vapor cools, it condenses into droplets that form a cloud, warming the surrounding air.
10:39The now warmer air rises, creating more updraft, lifting more air higher into the cooler atmosphere, where even more water
10:48can condense, which further warms the air.
10:53If the conditions are right, with enough moisture rising into cold air above, this fuels a positive feedback loop that
11:01intensifies the clouds' growth.
11:13I see, like, a whole line of updrafts going up, so I like that.
11:18A lot of these tops today, they just look really strong.
11:24Sometimes you've got the towers going up, and they don't have the same kind of powerful look.
11:28They're bubbly like a cauliflower, but they're just a little less intense.
11:32Well, a couple of these, if you look at them, they just look like there's so many areas where it's
11:37just knuckly and explosive-looking.
11:42Oh! I just saw two big bolts strike way out there on the horizon.
11:51But I think something big is going to happen here. It's a nice, large, dark area.
11:56This is probably going to turn into a really strong storm.
11:58I would expect. I would hope.
12:01I'm trying to catch some lightning right now. I'm doing two time lapses.
12:05Lightning is an indicator that the updraft is tall enough to have ice and hail.
12:15Ice and hail are key ingredients that drive the most powerful rain bombs.
12:21But how does something as solid as ice or hail form and stay aloft in the atmosphere?
12:28When water vapor condenses in clouds, it releases an extraordinary amount of energy.
12:34That makes our clouds very turbulent and that lifts the air higher up in the cloud.
12:40At some point in time, that air will cross over what we call the freezing level to form things like
12:46snowflakes and hailstones.
12:49And that changing phase, of course, releases more energy.
12:55This energy, in the form of heat, drives the further growth of the cloud, expanding upward to the very top
13:02of the troposphere.
13:03Up to 12 miles above ground level.
13:08Above the troposphere sits a warmer band of air called the stratosphere.
13:13This warm air acts as a lid preventing the cloud from climbing any higher.
13:18So it spreads out flat, forming a distinctive anvil shape.
13:23So we've gone from the development of a tiny little fluffy cloud to these very tall, extensive storms that are
13:31now carrying around large amounts of hailstones and snowflakes.
13:37This storm is now seriously ready to do business.
13:42Lightning bolts are a telltale sign that a cloud has developed into a thunderstorm.
13:49Raindrops get so big, they're too heavy to be held by the cloud's updraft, and so it begins to rain.
13:56Or, if conditions are right, it can go on to develop into a violent rain bomb.
14:04To understand why some thunderstorms collapse into rain bombs, it helps to know what's going on inside that rain cloud.
14:13One way to uncover that is to analyze the stuff that falls out.
14:19Particularly hailstones.
14:21Icy chunks of a frozen cloud.
14:32Over the summer of 2025, storm researchers teamed up on a project called Ice Chip to collect hailstones from thunderstorms
14:41striking the Great Plains.
14:44The ground teams, the teams looking at what kind of hail fell at the surface, is really what made this
14:49campaign unique.
14:50Because other campaigns, you know, would go and look at storms with mobile radars, and that's a lot of great
14:56information.
14:56But only ours also tried to really fully characterize what kind of hail was down at the surface.
15:08The Ice Chip team brings the hailstones to a cold lab in Boulder, Colorado.
15:17Here at below freezing temperatures, atmospheric scientists Anthony Bernal Ayala and Becky Adams-Seelen process and analyze each of the
15:26thousands of samples.
15:28Large hailstones are extremely valuable in understanding more about the thunderstorm they came from.
15:35Once you get the hailstone, you can actually just go ahead and cut a thin slice out of it.
15:40And you polish it up so it's an even thickness.
15:43You can get a lot of information just by looking at the slice.
15:47You can see different rings in the hail, and much like tree rings, those represent different conditions under which the
15:54hail was growing in the storm.
15:57When we look at hailstones, and we look at the cross-section, one of the things that we look at
16:01is whether the layer is opaque or whether the layer is clear.
16:05When you look at that clear layer, you're looking at where there is a warmer sub-zero temperature, so it's
16:10a little bit warmer in the cloud, where liquid water freezes slowly.
16:14And because it freezes slowly, that allowed the air bubbles to escape.
16:18So it's going to be clear. There's not going to be a lot of air bubbles trapped in this layer.
16:21When you look at the opaque layer, because it's in temperatures in the cloud that are very cold, it's going
16:28to freeze very rapidly.
16:29So because it freezes very rapidly, it actually traps a lot of air bubbles in that layer, so it actually
16:35looks opaque.
16:36But why would a single hailstone have both clear and opaque layers? And what does that reveal about how the
16:44hailstone formed?
16:46The hailstone had to have been moving around in the storm to experience these different conditions and to create the
16:51different layers.
16:52We think that it's actually rotating somehow around the updraft to accumulate all those layers that we see in the
17:01cross section.
17:02These layers are evidence that the hailstones are continually rising and falling inside a developing thundercloud.
17:11This hailstone spent most of its time in very cold temperatures in the cloud, but for a very short period,
17:18it actually went through a warmer side of the cloud.
17:22Then it went back a very cold temperature, then it went back a warmer section of the cloud, where it
17:26probably fell, and then it was collected at the surface.
17:30To grow to two inches wide, this hailstone most likely spent over half an hour being lifted and dropped inside
17:37the storm.
17:39There's updrafts, there's downdrafts, there could be hail, there could be circulations or rotations inside that cloud.
17:47These intense storms are very turbulent. They have regions where air is rising very rapidly, sometimes at speeds of 150
17:56miles per hour.
18:00This mixing of hail and ice provides the energy necessary for the storm to produce thunder and lightning.
18:09In mature thunderstorms like the one that made Anthony's hailstone, immensely powerful updrafts can suspend over a million tons of
18:18hail miles above the ground.
18:21It's actually quite incredible that storms are able to suspend these large mass of liquid raindrops and of our ice
18:30like hail and snowflakes so high up in the atmosphere.
18:35What happens to this core of rain, hail and ice determines whether the storm remains a regular thunderstorm or unleashes
18:45a rain bomb.
18:52Dude, that looks freaking awesome. That's just plummeting. That's like a downburst happening.
18:58When you see that middle rain shaft area where it looks like a blob, that's usually a good tell-tale
19:04sign of a downburst happening.
19:06Wow, man. This is stunning.
19:13In a fully developed thunderstorm cloud, what goes up must eventually come down.
19:20The cloud's updraft begins to peter out as rising air cools and sinks back toward the ground as a downdraft.
19:29This is what happens in a standard thunderstorm.
19:34But in a rain bomb, things are different because in a rain bomb, a sudden, extremely strong downdraft overwhelms the
19:43updraft, causing the clouds' core of ice and hail to collapse all at once.
19:49Two processes drive this sudden downdraft intensification.
19:54The first is that as the rain and hail start to fall downward, they drag on the air. So they
20:00pull the air down toward the earth.
20:05When massive amounts of rain and hail begin to fall, they help generate a downward rush of air, which can
20:12act as the rain bombs trigger.
20:15But that's not all that's required to get a rain bomb started.
20:20The second, more important process that accelerates this developing downburst toward the ground is evaporation.
20:29Evaporation is a cooling process. You experience it when you step out of a swimming pool or your shower.
20:34When you've got drops of water on your skin, as these drops evaporate, your skin feels very cold.
20:41If winds blowing into the cloud are dry, they can rapidly evaporate raindrops, as well as melt ice and hail.
20:49This cools the surrounding air, making it denser and heavier.
20:55This very cold air, very dense air, has to sink.
21:00So it's going to rush toward the surface, taking all of that large mass of rain and hail.
21:07As rain and hail descend from the cloud, if they hit more dry air, the evaporation can accelerate further.
21:15As the raindrops fall below cloud base into this drier air, they will evaporate in that location too.
21:23This, of course, is going to really intensify that cooling process.
21:27This very cold, dense air then rushes toward the surface, creating these phenomenal scenarios called downbursts or rain bombs.
21:42The downdrafts can intensify into hurricane force vertical winds, driving the clouds' core of hail, rain and cold air downward,
21:51slamming it into the ground.
21:54Sometimes the downburst's rain can completely evaporate before reaching the ground, creating what scientists call a dry downburst.
22:05And all of these downbursts, both wet and dry, can strike in just a few minutes, in a remarkably narrow
22:13column, as small as just a couple of hundred yards across.
22:18And as our atmosphere warms, they're becoming more and more powerful.
22:24It's actually can be quite a frightening moment. There's a lot going on. There's lightning, there's hail, there's very heavy
22:31rain, and then, of course, the strong wind.
22:38Storm chaser Hank Schema has been caught under a powerful rain bomb.
22:43There was a day where I get slammed by a downburst.
22:53The rain really picks up and gets really strong. Everything turns white, and then, all of a sudden, I can
22:57see that I'm about to drive off the road.
23:01You can feel the winds rock in your car, and the winds are picking up sand and things in the
23:07road, and they're slamming them into your car.
23:10It's really terrifying and scary.
23:20Strong winds are a key element of downbursts.
23:25They slam cold air into the ground at high speed.
23:30And this air has to go somewhere.
23:33They can't go into the ground, so they spread out horizontally in all directions.
23:37So you see extreme surface winds.
23:40Cold air hits the ground and pushes out radially from the heart of the downburst.
23:46This outflowing air, remember, it's very cold, dense air.
23:51We refer to as a cold pool, because it is a cold pool of dense air.
24:00These advancing banks of cold air can kick up dust, creating the distinctive dust storms often seen in the American
24:08Southwest.
24:09Dusty cold pools are called haboobs, and they create all sorts of severe weather, including visibility issues, road accidents, and
24:20breathing issues.
24:22The dust makes the turbulent gust front of an advancing cold pool easy to see.
24:28But even when no dust is present, this billowing front of cold air is still there.
24:35And it's these fierce straight line winds that inflict the most damage.
24:41These winds are strongest near the surface.
24:45If you compare that to something like a hurricane, a lot of the strength in a hurricane exists higher up
24:51in the atmosphere.
24:53But for downbursts, they occur very close to the surface.
24:58Trees will just flap down to the ground, and these wind gusts are so strong that you cannot stand on
25:04your own feet anymore.
25:05In some cases, it can look like a bomb went off.
25:08Literally, that air hits the ground at low levels and spreads out in all directions.
25:14Those winds are what we call straight line winds.
25:18They are not turning like a tornado turns.
25:21They are following straight lines away from where the downburst hits.
25:35This might explain what happened to Aeromexico Connect Flight 2431, when it took off from Durango International Airport, en route
25:44to Mexico City.
25:46The rain, while heavy, was not extreme.
25:49There were storms in the area, but the tower had cleared them for take off,
25:54and had told them that they actually have headwinds, which would provide them lift for take off.
26:02Without realizing it, Flight 2431 flew through a downburst.
26:07In just seconds, the plane experienced a near 180-degree shift in wind direction.
26:13The plane was about 30 feet off the ground at a very susceptible time on any take-off.
26:20And this tailwind, it swung from being an uplift to a sinking motion.
26:26Without the lift generated by a headwind, the plane plummeted and crashed into the runway.
26:53Luckily, everyone managed to escape before the plane was fully engulfed in flames.
27:00This wasn't the first passenger jet to crash in similar conditions.
27:06June 1975
27:09Eastern Airlines Flight 66 crashed on approach to JFK.
27:16August 1985
27:19DELTA FLIGHT 191
27:21CRASHED ON APPROACH TO DALLAS-FORT WORTH
27:26July 1994
27:28U.S. AIR FLIGHT 1016
27:31CRASHED ON APPROACH TO CHARLOTTE DOUGLAS INTERNATIONAL AIRPORT
27:37CRASHED ON APPROACH TO CHARLOTTE
27:38Those tragic accidents in the 70s and 80s led to a lot of very significant research in downbursts, how they
27:45operate, and then subsequently the technology that we need to warn pilots.
27:51A lot of the airports in the U.S. are fitted with these weather radars, but there are many of
27:58the airports around the world do not have this technology.
28:01Air Mexico Flight would not have taken off had they been aware of the fact that they were just about
28:07to hit a downburst.
28:11When investigators study the loss of the supposedly unsinkable Bayesian yacht, which went down on August 19th, 2024, they discover
28:21that before it capsized and sank, it had dragged its anchor around 400 yards in a dead straight line.
28:29The Bayesian was anchored off the north coast of Sicily. It was in a bay. It was next to another
28:38yacht.
28:39This CCTV footage from a camera on shore about 600 feet away reveals the boat in the distance.
28:47What ended up happening was as these really strong straight-lined winds hit these yachts, they dragged anchor in straight
28:55lines that indicates it was a straight-lined wind as opposed to the kind of rotational wind you would get
29:01from a tornado.
29:02It was a very large yacht with a very tall mast and it would appear that the downburst and associated
29:10cold pool was actually able to roll it over beyond its point of stability.
29:15The yacht succumbed to the same type of extreme low-altitude straight-line winds that led to the crash of
29:22Flight 2431.
29:30At the Puckle Pop Festival in 2011, the hail and howling winds struck an area less than 100 yards across.
29:39This was a very narrow downburst. This is what made it so unusual. You would normally expect such power from
29:46systems that are larger, where they can transport more rain and more hail and more wind to the surface than
29:53in a 100-meter-wide downburst. So a really remarkable event.
29:57These real-life tragedies revealed the destructive potential of powerful rain bombs. Intense, highly localized, and short-lived.
30:12But a storm that hits Houston in May 2024 has all the hallmarks of a downburst, except that it is
30:21much bigger.
30:23It travels around a thousand miles, and it lasts much longer than a single downburst. More than 12 hours.
30:32The line of severe thunderstorms is racing into a greater Houston area.
30:36You should batten down the hatches for the potential for straight-line wind gusts at about 70, 80 to 90
30:42miles an hour.
30:45National Weather Service forecaster Amaryllis Cotto is on call at the Houston-Galveston office, 27 miles southeast of downtown Houston,
30:54when the storm hits.
30:57The storm developed very fast in areas of west-northwest Texas at around 9 a.m., and so we could
31:05see how fast it was moving.
31:06It was already affecting the Houston metro area by around 5 to 6 p.m.
31:12It's not safe to be outside. We've got about 20 minutes to get hunkered down on the first floor, interior
31:18room of your home, away from windows.
31:20That's the safest place to be until this severe storm passes through.
31:23It was devastating, Houston. We had a lot of tree damage. We had millions of people without power.
31:31Hank and Neti Ashima are 5 miles north of downtown when the storm hits. He starts recording the storm from
31:39his car.
31:41Suddenly, it goes from daylight to darkness, and chaos hits.
31:49Here it comes.
31:52Oh, f**k! Oh, f**k!
31:55Yep, hang on. Got it.
31:59Um, we should not be here.
32:02I'm checking right now.
32:04You can't see a block in front of you just because of the whitewash of wind and rain, and trees
32:10are swaying, and downtown Houston is raining glass as windows are failing all up in the skyscrapers.
32:19The winds associated with this system were hurricane-force winds in the lower levels.
32:24It sucked windows out. There was glass everywhere. And in addition to the sucking motion, inside the buildings, the pressure
32:33in is now higher than outside.
32:34So you get this explosive force that forces windows and glass out of the buildings.
32:45It's the signature of a rain bomb.
32:49Super-strong, ground-level winds shattering any weak windows along their path.
32:55Telltale signs of straight-line wind damage are seen all over the city.
33:01They pull down power lines across Houston and plunge one million people into darkness.
33:08But the Houston storm isn't the size of the storms that hit Pucklepop or Sanctobasian.
33:15It's over 50 miles across, and leaves a path of devastation across the 10,000 square mile Houston metro area.
33:24Rain bombs just don't grow this big on their own.
33:27They need to gang together to become this large.
33:31But how?
33:37Rain bombs just don't grow this.
33:38Rain bombs just don't grow this much.
33:46Rain bombs just don't grow this in the middle of the cold.
33:47Rain bombs for rain bombs.
33:4822 miles northeast of Fort Collins, Colorado.
33:51Atmospheric scientist Sue Vandenhiever's 20-strong team is out in the field.
33:57I think the porkheads are keen to have some surface measurements.
34:00Okay, you're seeing.
34:01the moisture her team deploys drones engineered to withstand extreme weather they measure the
34:09outflow winds when the cold air in a downburst crashes to earth and races across the landscape
34:16forming the cold pool
34:24we've launched what we call the flying curtain
34:29and we're flying a wall of six drones we have a lower level of drones and an upper level of
34:36drones we have a lot of instruments that can measure the temperature the moisture of the
34:41atmosphere we've got anemometers on there that can measure the winds and this allows us to make
34:47measurements of the variability of the atmosphere and as the cold pool advances on us and blows
34:52through us we are able to make that measurement in time as well so there's a lot that we are
34:58characterizing about these coals
35:02sue and her team are tracking a storm a safe distance away beyond the horizon
35:09radar shows that it has produced a downburst of intense rainfall
35:16the air that slammed into the ground is now spreading out across the plains in a cold pool
35:22coming toward them their radar tracks the dust kicked up by the advancing bank of fast moving cold air
35:33so we're expecting a cold pool to come through within the next few minutes so we're waiting to
35:39try to collect the data the team will release weather balloons up into the cold pool to measure temperature
35:46pressure humidity and moisture
36:05this cooling of the air you can feel and the windy feeling that's this boundary that's actually
36:10starting to hit us so that we're going to release that balloon everybody ready three four one
36:21come on there's some thunder please release
36:3730 minutes after the rain bomb dropped that bank of cold air here graphically rendered to be visible
36:44has covered the 17 miles from the epicenter of the storm and breaks over the flying curtain of drones
37:05so right here we're we're looking at data from the balloon that we just launched what we're looking
37:10at is pressure moisture temperature and relative humidity and this is telling us the depth of the
37:17cold pool that just came through so right now based on the temperature data we're seeing a decrease in
37:22temperature that is going about 500 meters high the team has learned the cold pool reaches 500 meters or
37:31about 1600 feet high but that's not all these balloon observations allow the team to measure what's
37:38happening to the air above the advancing cold pool what they found is that the cold pool acts as a
37:45wedge
37:46pushing up an updraft of warm air when we have a storm forming a really strong downburst and its
37:53associated cold pool that lifts the surrounding air up and over the edge of the cold pool and forms a
37:59new
37:59updraft that updraft can go on to build another really strong storm that storm can then of course make
38:05its own downburst its own new cold pool which can then form another updraft and so we get into this
38:11cyclical
38:12process of after a formation background winds can stretch downburst cold pools from circular outflows
38:22into fan-shaped fronts if atmospheric conditions are primed for multiple thunderstorms the cold pools
38:30can merge into one broad line of advancing cold air the advancing boundary lifts warm air ahead of it
38:38this rising warm air feeds a new generation of updrafts and helps build an even larger storm
38:45it's a self-sustaining cycle of updrafts downbursts and cold pools that sweeps across the landscape
38:54meteorologists call this a derecho
39:00one thing that distinguishes derechos from other types of wind systems is their sheer size and how long
39:06they can last the longest one on record is some 1300 miles the ratios can stick together for time
39:13periods of 6 to 12 hours so these are extensive very dangerous wind storms
39:22the 2024 houston storm was a derecho an organized system of multiple repeating downbursts
39:30that ripped across a thousand miles of gulf coast from central texas to the florida panhandle
39:47back in arizona mike has a hunch that the beginnings of a multi-storm system
39:52are brewing west along interstate 8. oh man this storm big towers in there oh man this is this looks
40:02freaking great
40:12oh my god look at this demon holy brain bombs now that's a downburst
40:21we have a monster rain bomb right here a downburst of like that we haven't seen so far
40:28i mean this looks like a bomb went off that thing just collapsed right on those mountains
40:33and all that air is just exploding and hitting us this is awesome i could see the towers up there
40:41they
40:41were probably 50 000 plus they were kind of twisting even right here i see like this updrafts
40:47it's got a little twist to it and when that happens it's suspending that rain because it's rotating so
40:53suspending up there more so then when it comes down it just has so much more force and all that
40:58air all the stuff we're feeling it's just blasting from that storm and it's constant because there was
41:03probably multiple downbursts that happened there was like an initial one there there was one on the
41:08right one on the left and then just like the main thing went down and now we're getting this dust
41:13that's appearing right here
41:17the dusty outflow winds from the rain bombs are racing west and mike jumps in his vehicle to get
41:24ahead of the growing storm and reset in a new position
41:36there's you can kind of make it out so we actually have a dust storm coming
41:42so just overall it's getting better as it goes west
41:50ooh lightning this dust in there is looking good this dust is just food coloring in the atmosphere
42:00basically the dust and this shelf structure are showing us the outfloor of the cold pool where
42:05it's all consolidated and pushing but without the dust you don't get to see what the air is actually
42:09doing this is gorgeous the color this is what this is what you live for but this is the result
42:14of stronger downbursts that consolidated and just formed intense outflow
42:22this is amazing what
42:33it's making them disappear now
42:44what a day what a day
42:54this dust storm produced winds of over 55 miles per hour
42:59it was the result of multiple microbursts organizing into a larger system creating a macro burst
43:07if this dust-filled cold pool had hit phoenix instead of the desert it could have caused extensive damage
43:15and if it had grown further it could have become a derecho exactly what hit houston
43:24downbursts and derechos are dangerous wherever they strike but especially so when they hit built-up areas
43:32so is there any way to protect against them
43:35so is there any way to protect against them
43:48ian giamanko is lead meteorologist at the insurance institute for business and home
43:53safety the ibhs his team investigates how a downbursts devastating combination of wind and hail
44:00inflicts damage on property
44:03when wind attacks a building it's always looking for the weakest link in that chain
44:08and a lot of times that is at the edges of roofs or if an opening say a garage door
44:13a window a door
44:15fails and that air is allowed to rush in
44:20they use a monster wind tunnel to test the construction standards of north american homes
44:27an extraordinary array of 105 fans
44:32each fan is almost six feet in diameter and packs 350 horsepower
44:39together they can produce winds topping 100 miles per hour just like the houston direction
44:50wind is a cascade of damage
44:53it often starts with one little thing that cascades to the next to the next to the next
44:59and the next thing you know you're looking at a catastrophic failure
45:06to reinforce homes against the destructive power of downburst winds ian and the team at ibhs have
45:14developed a new building standard it's designed to help minimize the amount of damage that comes with severe
45:21wind events
45:25the ibhs construction methods include a hail resistant roof and also adds anchors and metal
45:32connectors to lock the roof to the walls and the walls to the foundations transferring the wind's force
45:39down into the ground
45:42build a home to these standards and put it alongside a typical home and the difference is clear
45:55as our wind speeds increase the front door fails
46:00that allows wind to rush into that structure and start pushing out fortified home however sitting on
46:07its right it's structurally sound it can take those forces whereas the conventionally built home simply
46:12couldn't and the next thing you know the wall has failed
46:33as our atmosphere warms it's simply producing more fuel for thunderstorms it's air that wants to go up
46:39those thunderstorms can take advantage of that in the warming world you can store more water vapor
46:45in the air so as we have more of this fuel in the air that can then condensate and release
46:50heat
46:50these thunderstorms that the ratios can become more intense
46:55as the world warms there will be more moisture in the atmosphere on average
47:01but some regions could actually dry out
47:30more evaporation and melting may mean there is less precipitation
47:33hitting the ground but it also means faster falling cold dense air
47:39and so there's every reason to expect with changing climates stronger downbursts
47:45the ratios already became more powerful over the last 40 years because the air is warmer over the
47:52u.s nowadays than it was in the 80s so this is a race to get our building codes and
47:57get our structures
47:58ready to deal with what could be the weather of the future protecting homes and businesses will reduce
48:07the financial cost of future downbursts and derechos and better forecasting is also essential
48:15but weather forecasts face limits because of the inherently chaotic nature of the atmosphere
48:21weather if you start a model with slightly different initial conditions the end results can be very
48:29different based on some very simple differences in the initial information we put into our models
48:36we can't actually accurately predict the weather beyond about 14 days
48:41by updating the model every few minutes with live data the forecast can be nudged back to reality
48:49but data quality is crucial and some of the best data comes from space-based instruments
49:01the weather
49:02french guiana
49:10an arian-5 rocket delivers a 4.2 ton next-gen weather satellite into a geostationary orbit
49:18where it stays positioned above europe and north africa
49:22it's one of three satellites that will be co-located in the same orbit to probe the region's atmosphere
49:31olivier breeze is part of the team behind this new satellite system
49:36the meteosat mission is a geostationary satellite you have a constant and stable view of the earth
49:46the aim is to improve the short-term now casting and also to provide alerts on a severe weather event
49:53on a very short term within one or two hours and within a very small area on a valley on
49:59a village or in a town
50:05these satellites will provide a 3d profile of the atmosphere above europe and north africa
50:11including humidity wind speed and temperature
50:19this real-time view will enable forecasters to spot the warning signs of an atmosphere primed to
50:26produce downbursts rapidly cooling cloud tops or banks of dry air around developing thunderstorms
50:34allowing forecasters to give downburst warnings
50:41for us working on this project we are convinced that we are in a position to save lives
50:48so far the u.s has no equivalent geostationary satellite system but there are plans for future deployment
50:56we want to save lives around the world we really need global observations and so the best way to do
51:04this is to build satellite platforms we've made progress with the forecasting of extreme downbursts
51:11and derechos but there's still a lot of things that we don't know about them however our modeling
51:17systems our observational systems and our field campaigns have allowed us to really move forward with
51:23understanding these storms and better predicting them earth's atmosphere is a cauldron mixing warm
51:31wet air with cold air above a mixture that generates huge thunderstorms and as the earth's atmosphere
51:38warms it will hold more moisture and more energy to fuel them as we move forward with new satellite
51:45technology i believe that our ability to forecast these systems will be even more improved in the next
51:51zero to ten years but while we wait for forecasts to catch up more severe winds more deadly hail
52:00and more extreme rainfall will mean more devastating rain bombs
52:23so
52:34so
52:35so
53:04Transcription by CastingWords
53:14CastingWords
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