karen davis, the nurse who survived the entrapment in the mega fire in paradise, california, says she lost everything in the inferno. battling the trauma from the flames, she decided to move to las vegas to be closer to her daughter and rebuild her shattered life. once there, karen continued her career in health care. she also decided to become a member of the henderson, nevada, community emergency response team, aiming to help others in future emergencies. a testament to her inner strength and resiliency. for more information on what you can do in a wildfire and how to combat the growing climate crisis, please go to cnn.com/violentearth. i'm liev schreiber. thanks for watching. good night. ogo]

jess phoenix: one of the major hazards from volcanic eruptions are pyroclastic flows. [indistinct shouting] the rock fragments and the gases are moving at speeds like a jetliner. man: [speaking spanish] jess phoenix: it will obliterate trees. it will take out people. it can even reshape the geology of the area. nobody can outrun a pyroclastic flow. if you are faced with one, you are dead. welcome to violent earth.

i'm liev schreiber. more than 80% of the earth's surface was forged by volcanoes. they helped create fertile soil for agriculture, and volcanic gases helped form our atmosphere. without volcanoes, we would not have life on earth as we know it. all around the world, every single day, there are 40 to 50 volcanoes erupting under sea, on land, sometimes even under ice. our earth is a living, changing planet. but when a volcano erupts, it also has the power to destroy, like it did in 2018 at mount fuego in guatemala, when a massive eruption buried the surrounding towns in over 6 feet of volcanic ash in a matter of minutes. [music playing] george kourounis: mount fuego in guatemala is your stereotypical stratovolcano--

the steep sides, crater at the top, erupting quite frequently. patrick oppmann: and so people are very much used to the idea that the volcano is this living thing. that was really considered normal here and not cause for alarm. but in 2018, at fuego, activity had been sort of ramping up. man: [speaking spanish] patrick oppmann: the volcano had been rumbling for several days. june 3, around the middle of the day, a lot of people actually got closer to the volcano to get film, get video, get photographs, not thinking it was going to be dangerous. jiuwit rosas: [speaking spanish] interpreter: i had a friend indicating to me that the volcano had begun a more eruptive phase. patrick oppmann: jiuwit was working in support of local emergency services, and they told him to come up because they were going to begin setting up a shelter in case people had to be evacuated. jiuwit rosas: [speaking spanish]

interpreter: when we arrived at the bridge area, i got out of the vehicle and started recording with my camera. patrick oppmann: shortly thereafter, you see this huge cloud coming down the mountain, just sort of engulfing a whole side of the volcano. jiuwit rosas: [speaking spanish] interpreter: we did not know what the danger was that was coming towards us. when, suddenly, we began to see that it was coming closer, closer, and closer. man: [speaking spanish] the volcano unleashed one of its most deadly weapons, a powerful pyroclastic flow. pyroclastic flows are hot, fast-moving currents of ash and gas. michael poland: they can go incredibly fast, hundreds of miles an hour, be hundreds of degrees in temperature. and they will just wipe out anything in their path. alexa van eaton: it's very rare to be able to survive the hot interior of a fast-moving pyroclastic flow.

the reason for that is that there's no oxygen to breathe. it's suffocating, and it burns you to a crisp, essentially. these have been known to overrun entire cities. this is what took out the towns of pompeii and herculaneum. people think that lava is the most dangerous part of a volcano. but in reality, it's pyroclastic flows. jiuwit rosas: [speaking spanish] interpreter: i felt like i couldn't breathe well anymore. the lack of oxygen at that moment was evident. it was a very strange sensation. i said, we must act. patrick oppmann: and that's when they make the fateful decision, he and the group he was with, to jump in the pickup they have. they start racing down the mountain. jess phoenix: volcanoes are one of the most fascinating geologic features on planet earth.

they are essentially windows into the beating heart of our planet. george kourounis: most of that magma that's inside earth is contained within that crust. but every now and then, in certain places, that liquid rock makes its way to the surface, sometimes violently. brad pitcher: one example of these locations are areas where tectonic plates are being ripped apart from one another, like iceland. alexa van eaton: every volcano has its own personality. they look different. they behave differently. they erupt on different timescales. there are volcanoes that they don't even look like volcanoes. yellowstone is a great example. there are fields of volcanic activity. there was never a huge mountain in a place like that but, rather, volcanism was spread out over a very broad area. george kourounis: if you wanted to classify volcanoes in the most basic division, you've got red, effusive volcanoes, where you have

liquid lava pouring out, and then you've got the gray volcanoes. those are the ones that explode with pulverized lava that comes out as ash. and these gray volcanoes are the ones that you really have to watch out for. brad pitcher: fuego volcano is more of a gray-style volcano. patrick oppmann: they're the ones that don't erupt as often. but when they do, they can be absolutely catastrophic. man: [speaking spanish] jiuwit rosas: [speaking spanish] interpreter: when we got into the vehicle, the driver accelerated in a matter of seconds, to almost 100 kilometers per hour. man: [speaking spanish] jiuwit rosas: [speaking spanish] interpreter: and yet the cloud was very close to us. george kourounis: there are numerous people standing at the side of the road, seemingly in shock, not fully understanding the danger they're in. you see this gray cloud envelop them as the car motors away.

the thing that got me is the woman who is encouraging to drive faster. she's just saying, [spanish]. woman: [speaking spanish] jess phoenix: "don't stop." woman: [speaking spanish] patrick oppmann: and as they race off down the mountain, they're honking the horn. you see people still on the side of the road. they're driving by people who probably only had seconds or minutes more to live. george kourounis: there are about 800 million people that live within 60 miles of a volcano on planet earth. alexa van eaton: at fuego specifically, there are communities as close as five miles or so from the summit of the volcano. patrick oppmann: unfortunately, many of them were caught up in this pyroclastic flow. [vehicle horns beeping] jiuwit rosas: [speaking spanish] interpreter: we were shouting inside the vehicle, get out, evacuate. [vehicle horns beeping] man: [speaking spanish] jess phoenix: the video is a really poignant reminder of how

sudden and how unexpected these eruptions can be and, unfortunately, how deadly. [horns beeping, siren wailing] patrick oppmann: jiuwit said when they got to a safe area, much lower, then they got out and they realized they were covered in ash, that the car had been damaged. it really is miraculous that they survived at all. jiuwit rosas: [speaking spanish] interpreter: what would have happened if we had waited 10 more seconds? we would not have had time to escape. it really was seconds and distance that gave us the advantage of being able to get away. [music playing] it's hard to believe that this used to be a neighborhood where people lived. there were houses here. this was the main street. and now it is just tons and tons of volcanic ash. it is an incredible sight to see, and it makes you wonder if anybody

could ever live here again. michael poland: the official death toll was over 200 people. but there are still many people that were unaccounted for. [music playing] jiuwit rosas: [speaking spanish] interpreter: there was a community. now, there is only rubble and sand.

michael poland: there's a number of warning signs that volcanoes give. as magma rises, it starts to break rock apart, and that creates small earthquakes. there were some that were recurring in the area. george kourounis: then they started getting more intense and more frequent. michael poland: you'll see changes in the shape of the ground as magma rises because of the pressure that's building beneath it. don swanson: as this magma was slowly rising in mount saint helens, it was shoving the north side of the volcano outward at a rate of about 5 feet a day. george kourounis: it was eventually 400 feet, extending out from where the original side of the volcano had been. jess phoenix: unfortunately, we can't predict exactly when

volcanoes are going to erupt, how long an eruption will last, or how big it will be. george kourounis: mount saint helens was having these smaller eruptions, but that pressure just kept building up and building up until it was on the brink of exploding. that sunday morning, may 18, there were a variety of people who were scattered around. reid blackburn was northwest of the volcano. fay blackburn: reid was born on the east coast but, when he was about 10, moved to oregon. he was funny. he had a very dry wit. if you got to know him, yeah, he would become your best friend. reid was quite an outdoorsman. he bicycled. he climbed mountains. he backpacked. we both worked for the columbian newspaper in vancouver. steve olson: he was doing a time-lapse series of photographs of the volcano. fay blackburn: and so he was camped up there,

7 or 8 miles away from the mountain. they considered it safe. don swanson: but when it erupted, the scale was far bigger than we anticipated. [music playing] on the morning of may 18, i was in vancouver. and suddenly, the traces on the seismograph started just moving back and forth, back and forth. george kourounis: the side of the mountain gave way. and what was once a beautiful, serene forest turned into hell on earth. that big bulge on the side of the volcano actually slid away. avalanche is the largest landslide in recorded history. michael poland: and as the volcano failed, it instantly exposed the magma that had been accumulating in the volcano itself to atmospheric pressure. and it's like shaking that can of soda and then opening it. all of the gas that was trapped in that magma suddenly came out.

there wasn't a vertically directed explosion the way we typically think of a volcanic eruption. instead, it blasted out sideways. brad pitcher: so when this lateral blast occurred, it was this hot gas and ash and pulverized rock that traveled at speeds of 400, possibly even 500 miles per hour, creating what we call a pyroclastic surge. i've sort of described it as a stone hurricane. it just obliterated everything in its path. michael poland: it dropped trees like matchsticks, and they were all radiated away from the volcano. the size of the devastated area was about the size of chicago. i rushed to the air park and jumped on a plane. there was this tremendous ash column rising out of the volcano.

some of the footage shows lightning in the cloud. one of the things that happens with an ash cloud around a volcano is that the ash, as it rubs across each other, generates static electricity and generates these huge lightning bolts. man: dirty thunderstorms, some people call it. alexa van eaton: and volcanic eruptions do create thunder. but there are also other thunderous components to an explosive eruption. you can have rapid expulsion-- man: ooh, [bleep] alexa van eaton: --and air pressure waves, essentially shock waves that create thunderous sounds. [loud eruption] reporter: perhaps for most people within washington and oregon, the real impact came in the form of choking, volcanic ash. for the folks that were in the ash cloud, really, day turned to night. and ash starts raining out of the sky. even in the cars, your eyes were watering.

your throat was burning. volcanic ash is not like fireplace soot. it's pulverized rock fragments that are very, very small. and when you get enough pulverized rock, it can destroy buildings. it ruins roads. it covers crops and can cause famine if there's enough of it. michael poland: ash and airplane engines don't mix well. ash melts at about the temperature that jet engines operate. so if an airplane flies through an ash plume and sucks that ash into the engine, it can melt that ash. and then it starts coating the engine. and it can cause the engine to fail. this happened in 1989 with the eruption of redoubt in alaska. a passenger, 747, flew into that ash plume and all four engines died. there was a recording of the pilots when they lost power to the engines. pilot assistant:

they hurtled through the air before they were able to regain their engines and have a safe landing. but this was a very eye-opening event. so that's why we see air traffic diverted because of a volcanic eruption. [music playing] we flew figure eights around the south side of the volcano all morning long. during that time, i just didn't understand how people could survive that. i was called by a friend. and, um, she said, did you know the mountain erupted? and so we started talking and saying, yeah, reid will come home now. about 1 o'clock is when i started getting worried because i hadn't heard from anyone.

[audio logo]

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the number one question i get asked about volcanoes is, is yellowstone going to erupt and kill us all? i heard it's due. [drum beat] michael poland: i think yellowstone has become a bit of a bogeyman in terms of volcanoes.

it's not really possible for any volcano to be overdue. volcanoes don't work that way. they don't work on schedules. george kourounis: the thicker part of the crust is moving over top of yellowstone. so the lid on that pot is getting more solid. so the odds of it erupting are actually reducing. but it's pretty much impossible to predict the exact moment in time when a volcano is going to erupt. michael poland: and anticipating the size of an eruption is still a real problem for volcanology. george kourounis: when mount st. helens erupted on may 18th, 1980, it exploded with such force, it took everyone completely off guard. [music playing] one of the people that was about seven or eight miles away from the volcano was a photographer named reid blackburn. i went to my sister's home and we started a vigil there.

i think we all thought maybe he'd get out. because by that time, they had footage from a reporter from a seattle station who had been camped up there. dave crockett (voiceover): i've left the car behind. and as you can tell probably from this picture-- [breathes heavily] --i'm walking towards the only light i can see on top of a ridge. i started up a logging road, and that's when the ash hit. dave crockett (voiceover): feel the ash now in my eyes. it's getting very hard to breathe. [breathes heavily] alexa van eaton: for those who were downwind of the ash fall, you couldn't even see your hand in front of your face. dave crockett (voiceover): it's pitch black, just pitch black. this is-- this is hell on earth i'm walking through. he had made it out on foot. and so we thought, well, maybe reid made it out. but he's just stuck in the wilderness someplace. [engine roaring] don swanson: we were flying around trying to figure out what had happened.

and in that process, we saw this car down there. so we thought, well, perhaps there's some survivors. they could see the car because it was in a clearing. but it was just all a sea of ash. jess phoenix: there was very little left of the vehicle that you could just see exposed. don swanson: reid blackburn was in a car. we could see his head. he was otherwise buried by ash. [music playing] i think he did get to see the eruption and would have run into his car for shelter. he gets in the car, hoping it's ok. but it isn't. steve olson: before he could turn on the car or move at all, the blast had reached him, blew out the windows of his car and immediately filled the car with ash. he would have drowned in the ash, essentially.

he would have died of ash asphyxiation. fay blackburn: when i got his personal effects back, his wallet, the leather disintegrated. but the cards inside it, they just look like they're burnt on the edges. on the envelope, it did say, body number 11 skeletonization. so to me, that means there was no flesh left on his body. that's how immense that magnitude was of that blast. [intense music] alexa van eaton: there are lava flows that reach the ocean. and there are tour boats who drive up. from out of nowhere, comes lava bombs. [people screaming] [crashing]

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while reducing the web traffic local papers rely on. so tell lawmakers, support local journalism, not well connected media companies. oppose ab 886. paid for by ccia. oppose ab 886. [music playing] george kourounis: the hawaiian islands are fascinating. as the pacific plate moves over a hotspot under our crust, it forms these islands through a series of volcanic eruptions. the most active volcano on the big island is kilauea. [drum beat] woman: when people think of volcanoes,

they often think of those tall, pointy volcanoes. kilauea is different. it's a shield volcano. it's flatter. and it has, sort of, gentle slopes that lead down to the ocean. scott mclean: there's several neighborhoods, and communities, and houses that are built on the actual volcano. it was pretty benign, at least in the past few years. and then in 2018, everything changed. [music playing] alexa van eaton: there were essentially two eruptions in one. there was explosive activity at the summit. and then there were fissures opening up with fountains, essentially curtains of lava rising tens to hundreds of feet into the air. those fissures opened up into neighborhoods. reporter: many residents have been forced to evacuate their homes, and they're not sure when,

or whether they'll have anything to return to. [picture flash] volcanoes emit a range of gases. when you have an erupting fissure, there's so much gas coming out so forcefully. it can actually sound like the roar of a jet engine. during eruptions, those gases can escape significantly more and can create what we call vog, or volcanic fog. and it happens, when you get these small particles of sulfur dioxide gas that can be suspended in this humid air, it burns your eyes, stings your skin. lava is almost difficult to wrap your mind around. it's liquid rock, about 2,000 degrees fahrenheit and molten. the heat that you experience when you're close to lava is almost undescribable.

for the most part, lava flows travel slowly. and there are things that you can walk away from. on rare occasions, they can be very fast. if they're in a channel, they flow like a river, many, many miles per hour. [music playing] alexa van eaton: in 2018, there were lava flows that reached the ocean in what's called an ocean entry. and there are tour boats who drive up to the lava ocean entry. reporter: a group on a tour boat was getting a close look early monday morning when something terrifying happened. from out of nowhere, under the ocean, comes lava bombs. [people screaming] alexa van eaton: lava bombs are large chunk of magma or lava that's been expelled from an explosive eruption.

they're really hazardous. you don't want to get hit by one of these. lava bombs are stunningly terrifying. these things can move up to 190 miles an hour and are anywhere from the size of a golf ball to a small suv. as these lava bombs fly through the air, they get cooled. so when they hit you, it's not like you're getting hit by some sticky lava. you're getting hit by a piece of rock that is still extremely hot. [people screaming] reporter: a clump of rock ripped through the roof of the tour boat. nearly two dozen people were hurt. 13 of them were taken to the hospital. so it caused actual injury. now, nobody died. but it is a real example that you cannot predict everything about a volcano. alexa van eaton: people, for years, have been able to boat ride up to that lava ocean entry.

and so even when you think you know a volcanic hazard, it can change on a dime. [music playing] reporter (voiceover): this really does look like hell on earth in a place that is heaven for so many people who live here. [music playing] kilauea erupted at a series of 24 fissures. where the lava was really flowing, there was a whole bunch of locals there. daryl clinton (voiceover): you might want to step back on this one. we knew that there was this guy, daryl clinton, trying to protect his friend's house. reporter (voiceover): uh, where's the safest place to be? daryl clinton (voiceover): i don't know. and we quickly put a microphone on him and just started asking him questions. reporter (voiceover): so, daryl, why the hell are you here? daryl clinton (voiceover): oh, i'm just trying to save these structures for, uh, some friends of mine.

daryl, who's strong-willed, he doesn't want to abandon the house. so he stays behind. it was close to one of the lava vents that opened up. and he was staying there to put out fires. man: when the lava came in, he would douse it with water. where darryl was-- the jet sound was just continuous. man (voiceover): you're good. you're good. you're all safe. the fissure near daryl was number 17. fissure 17 was the first one to really, really dump volumes of lava. it was very explosive in nature. it was hard for me to believe that anyone in their right mind would want to be there. man [voiceover]: you're all right. reporter (voiceover): when you hear the explosions and you're out on the lawn, what's the strategy?

daryl clinton (voiceover): look up and watch them. keep your eye on them. reporter: that was the strategy. and it worked pretty well for him, until it didn't. friday we interviewed him. and on sunday morning, we got word that somebody had been hit by a lava bomb. and as soon as i heard that, i was 1,000,000% sure that's daryl. there i was upon the third floor deck. most of the lava bombs were ejected pretty much straight up in the air. but every now and again, there would be one that would come out like a line drive. i was on the phone with daryl, and the line just went dead. [intense sound] i woke up. and i was on fire up against the wall. and, uh, that's when i knew something bad had happened.

it was a lava bomb. i knew i'd been hit with one of those things that i've been trying to keep away from the house all week. last one to hit the house, it got me. it's literally being hit by a boulder. so you'll break bones. you will immediately start getting third degree burns. daryl was on his porch. it's made out of wood. not only did it hit daryl, it also was so hot that it started a fire. there was lava rock all over. i was on fire. and i felt intense pain. [drum beat] i went to push myself up. and then i collapsed. and i looked at my leg and realized that my foot was pretty much detached. i think i'm going to bleed to death. i was like, oh, this is it. i'm dead. i'm going to die.

there was nothing i could do. i couldn't move. daryl was on the top floor of the house. he was lucky in that his ex-wife, lisa, had been there. [music playing] daryl clinton (voiceover): we drove about seven miles. and then eventually, an ambulance came. it was the most extreme force i've ever felt in my life, just so powerful. reporter: he had multiple surgeries. it was a long, arduous process. as far as recovery goes, he'll never, never be recovered. however, he's a remarkable person and adapts, and goes on. 700 houses were completely destroyed. 2,000 people were displaced from their homes. a whole section of this part of the island

was completely reformed forever. how can you not show a little bit of respect to mother nature? because, i mean, daryl's story is a perfect example of what nature can do. [audio logo]

] so on may 18th, 1980, the eruption sent an ash flow that just spread out across the landscape. and it absolutely devastated the region. it knocked over all of the trees. it displaced water in several lakes. the blast itself extended far much farther than geologists had ever been anticipating at that point. george kourounis: because this was the biggest eruption in recorded history for the united states, nobody really knew what to expect. man: i have been given some information. the toutle river has a log jam and a wall of water about 6 feet high. venus dergan: the weekend of may 18, my boyfriend at the time, roald reitan and i decided to do a weekend getaway of fishing down at a fishing

hole down by mount st. helens. our campsite was on the south fork of the toutle river. we were about 25 miles to 30 miles from mount st. helens that morning. we did not hear a huge boom, or a huge blast, or anything like that. we could hear rushing water. and we could see the river rising towards our tent. roald looked up. and we saw this huge train trestle coming downstream towards our campsite. and it was holding back a bunch of debris like logs and mud. and we looked at each other. and we-- we need to get out of here. [intense sound] [music playing] brad pitcher: coming down the river valley towards them was a wall of ash, and rock, and trees called a lahar. alexa van eaton: lahars are fast moving mudflows created by melting of snow, or ice, or lake near the summit

of an erupting volcano. of course, mount st. helens was covered in snow, ice, and glaciers. and all of those almost immediately melted. as that water starts flowing down the mountain, it's picking up all kinds of material as it goes. and that builds this really thick slurry that makes up a lahar. imagine a flash flood. but instead of water, it's hot cement filled with boulders and tree trunks. these lahars, they can travel tens of miles away from the eruptive site. you don't even have to be close to the volcanoes. and they obliterate everything in their path. man: it is estimated by aerial observers that the initial flash floods on this river expanded it to two to three times its normal width. ray jennings (voiceover): trees 100 feet high come down that river, standing straight up. there was so many logs around them that the trees

couldn't fall over. venus dergan: when you think about an eruption, you think ash. you don't hear about lahars or mudflows. that was never even a thought in our mind. we jumped into the car, but it was moving pretty fast. they figure it was probably about a 30 foot wall of mud and debris that hit our campsite, going between 20 and 30 miles an hour. it was starting to come into the floorboards. roald and i decided to get out of the car and jump on top of the roof because we didn't want to get trapped inside. it just threw us right into the center of the mudflow. and we started being swept downstream. steve olson: the river was covered with a very thick mat of logs at that point. roald was able to land on top of a log. but venus ended up in the water. venus dergan: i was just engulfed in timber, and branches, and mud. i was bobbing up and down in the mud and the water. and i could hear roald screaming to hang on behind me. it was the most terrifying scream that i had ever heard.

that's when terror set in. and i knew we were in really, really bad trouble. i went under a couple of times. and i thought, this is it. i can't survive this. i can't fight this. there's nothing i can do. [audio logo]

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reporter: this is colombia's newest national cemetery, the once thriving river community of armero buried under thousands of tons of mud. the worst lahar that ever occurred was the eruption of nebahat del ruiz in 1985. it was a relatively small eruption, but the volcano was covered in snow and ice. and that fed a really large lahar that went many, many miles down a river valley and absolutely destroyed the community of armero. man (voiceover): a mile-wide river of mud 15 feet deep. brad pitcher: when it comes to rest, now you've got this hardened, almost like concrete substance that can be, like, quicksand when people are trying to get out of it. and because this town was almost completely covered, rescuers had no real means of getting in to help anyone. [music playing]

it killed over 20,000 people. brad pitcher: what is terrifying about the nebahat del ruiz eruption is that there's another volcano in the united states that has eerie similarities to that volcano. and it is mount rainier in washington state. jess phoenix: mount rainier keeps me up at night because it poses such a great threat to the surrounding communities. tacoma and south seattle are built on 100 foot thick, ancient mud flows from eruptions of mount rainier from millions of years ago. george kourounis: the summit is very cold, lots of snow, glaciers, ice. and when it eventually erupts, that is all going to melt very quickly and head towards these towns below. in fact, it has about eight times the amount of glaciers and snow as nebahat del ruiz had when it erupted in 1985.

man: there's the potential to have a much more catastrophic mudflow. [music playing] these things can be very destructive if you get caught in one. the chances of survival are minimal. there's only a few stories of people that have survived being in lahars. [music playing] venus dergan: i just was praying that i would be able to swim or crawl out of it. [music playing] i tried to hang on as we were being swept downstream. the bark on the trees were just scraping. i could feel it on my legs, on my arms. she can't really pull herself up. and the logs are too big. reporter: that lahar flow took out hundreds

of homes and other structures. 27 bridges altogether were knocked down. venus dergan: at one point, i went under the logs and the mud. and i just resigned myself that this was it. i wasn't going to get out of this and that i was going to die. the next thing i knew, roald somehow got to me and grabbed my arm. and he physically yanked me up out of the mud, up onto the log with him. and we hung on for dear life and just rode on this huge log down the river. and when it finally stopped, we jumped to the embankment. there was a huge hillside that we had to crawl up, full of shrubs and trees. and roald and i didn't have any shoes on because the mud flow had knocked our socks and shoes off. she's severely injured at this point. venus dergan: my wrist was fractured. the bark had shaved most of my skin

off of my face, my arms, my torso, my legs. it seemed like hours. roald finally found a clearing. and there were some men. he started screaming at the top of his lungs that we needed help. randy (voiceover): we helped him get her up on the bank. we covered her up. she was visibly in shock. i looked like a mud sculpture, is what i was told. they were trying to get it out of my eyes. it was in my hair. brad pitcher: volcanic ash is made up of hardened magma that has a bunch of gas bubbles in it. and so it becomes these sort of sharp, glassy fragments. and then if it gets on your skin, wiping that off can be, you know, extremely painful. venus dergan: by that point, my helicopter had come. the gentlemen lifted me up and put me into the helicopter. [picture flash] we were the only two at that point that they had found alive. but we won fate that day. fortunately, we survived on intuition and the grace of god.

[music playing] the eruption of mount st. helens completely revolutionized the field of volcanology. steve olson: it taught us an incredible amount about the dangers of volcanoes and the damage that they can do. alexa van eaton: and it changed the way we model volcanic eruptions. and so most models use the data from mount st. helens. jess phoenix: and it showed governments the importance of having a multidisciplinary team of emergency response personnel and scientists who were trained in different aspects of volcano monitoring. [music playing] now volcanoes are much better monitored in the united states, from the remote aleutian islands of alaska to the well-known places like mount st. helens and kilauea.

venus dergan: as humanity grows and humans take over areas of the planet where these type of events happen, we can't stop them. so we need to learn how to be ready when a situation like this arises. we'd have to learn how to coexist with it. it took venus more than two years to recover from her injuries. though she and roald eventually ended their relationship, they have stayed in touch, forever bonded. they were among the lucky ones. the eruption of mount st. helens was the worst volcanic disaster in us history. and 57 people lost their lives. for more information on volcanoes and what you can do to combat the growing climate crisis, please go to cnn.com/violentearth. i'm liev schreiber. thanks for watching. good night.