Remembering the eruption of Mount St. Helens. | KOIN Conversations

Added: 2026-05-20

[00:00:00]Well, hey everybody and welcome back into another coin conversations and today we are talking about something special very specific to this area. I've got my colleague and friend meteorologist Steve Pierce with me who was actually here to live to tell the tale about the eruption of Mount St. Helens. There it is in its pride and joy before the eruption. Look at that pointy top there.

[00:00:26]Steve, how you doing?

[00:00:28]I'm doing great. Good morning. Uh this is going to enter on the 18th, the anniversary. The 46th anniversary, right? It's a long time.

[00:00:36]46 years since that major eruption. One of the if not the most uh like largest or like what what what is the largest I mean volcanic eruption in the US, but um one of the most impactful geological things to happen in this country right in our backyard, right in your backyard. So 45 45 miles north and east of Vancouver. Yeah, it was the biggest eruption in the lower 48 since I believe Mount Lassen in the early 20s.

[00:01:09]Just incredible.

[00:01:12]And you know, I I wasn't around quite yet when this happened, but you were.

[00:01:17]You were at the sweet age of seven.

[00:01:19]Seven. In southwest Washington and I just I want to hear about your experience because this is, you know, a once-in-an-eon thing to happen for humans. You know, it's so fascinating to me that we got an eruption in our lifetime. And of course, other countries near more volcanic activity there have been eruptions, but um yeah, to have to have one in our backyard in Washington and also, you know, just having the Cascades in our neck of the woods.

[00:01:50]The the time scale of eruptions is so long in between these periods to to actually get one in the '80s, 1980, May 18th, um, is just so incredible to me.

[00:02:01]So, Steve, tell me about your experience, um, as a child when this erupted.

[00:02:07]Well, first off, I want to say that this was the singular most important event in my life that actually got me interested in meteorology. I wanted to know where the ash clouds were going. Now, keep in mind, we had the May 18th was the big eruption, right? Uh, and then we actually, a lot of people don't remember this, but the locals do.

[00:02:26]We had several more eruptions that came towards Portland, and that was May 25th, it was on Memorial Day of 1980. That eruption was equally as big as May 18th, not as long in duration, and the ash came directly over, yeah, as you see the picture there, directly over Portland and Vancouver, and then it rained on top of that. So, imagine an inch of ash falling, and then having it just pour down rain. Uh, gutters were literally breaking off of, uh, our houses. Uh, it was a, uh, that whole summer, another one on June 12th, that ash came right over Portland, canceled school, I remember, for the Vancouver district on the last day. That eruption that you're looking at right there, that, if you go back one slide, uh, it looks like a, um, an anvil on a thunderstorm, that was actually from a July 22nd eruption. Uh, yeah, that one right there. Uh, I remember that vividly, warm summer day, and then, of course, these pictures are from the actual May 18th eruption. These are the mud flows that came down the North Fork of the Toutle River.

[00:03:31]Uh, of course, everyone knows this was what's called a lateral blast, it happened at 8:32 in the morning on Sunday, May 18th.

[00:03:39]I just gotten out of church, uh, and we heard it on the news, everybody ran home and got on the TV. Uh, from a meteorological perspective, we had morning low clouds that day down here in the valley, so we couldn't, we didn't have a visual of the mountain until later in the afternoon once it started to break. Uh but up there, yeah, these these mud flows, these lahars, uh which was all melted glacial water uh coming off the mountain when that lateral blast came out and it started with a 5.1 earthquake. So it was the largest landslide ever recorded in history on planet Earth. And the resultant uh mud flows down the North Fork of the Toutle and several other uh local creeks and rivers up there obviously changed the landscape forever.

[00:04:23]Um hot gases and ash blew out laterally to the north over uh the lake behind me. Yeah, and did that to all of the trees. Literally Yeah. Took out miles of trees, too. Just >> You know, when when I when I learned about this in college, um the type of eruption um is a pyroclastic eruption.

[00:04:44]So it's a lot of, you know, ash and explosive gas and rocks. And it's not that, you know, running lava that you see from another type of volcano called a shield volcano like in Hawaii. And um my professors were just talking about how, you know, like when you're when you're making a sand castle and you fill a bucket with sand and water and it just compresses into this really heavy thick material. That's kind of what it did. It just filled in valleys. All this ash and rock filled in valleys while toppling trees. And just that type of damage is is um very specific to our >> Yeah. types of volcanoes here in the region. And we have so many valleys and trees that surround these volcanoes.

[00:05:26]Just imagine all of that getting filled in by ash and dirt and rocks and being leveled out for miles surrounding the blast. After the immediate blast went through, you know, Spirit Lake behind me, uh which had temperatures of 4 to 600° with that blast of uh superheated gases, um and yeah if you look closely you can see the uh North Fork of the Toutle kind of snaking down through that picture there. Mhm. One fascinating note is you know, little old Harry Truman, he was the old guy up there in his late 80s that would not leave his cabin. And his cabin, I don't know if you can see it, probably right over my shoulder, somewhere on that lakeside uh facing the mountain only 3 mi uh towards the north of the mountain.

[00:06:13]That is now covered by about 300 ft of sediment. And the amount of sediment that came down in the landslide pushed the entire It went under the lake and rose the level of Spirit Lake 200 ft. To this day, Spirit Lake is 200 ft higher because of all the sed- sediment that floated about 400 mph into the lake and basically raised it up. And it also blocked access to the Toutle River. The Toutle River is what would drain Spirit Lake right? All the way down to the Columbia River near Castle Rock. And the Army Corps of Engineers had to go in and build, and it's still there to this day, an 11-ft round tunnel.

[00:06:56]It's a tube that they bored through the basalt uh hillside. And now they can drain Spirit Lake manually to get it into the Toutle River because, again, it was buried.

[00:07:08]That whole south side of the lake behind me was buried in uh almost 400 ft of ash that day.

[00:07:13]So It's It's just so unreal to think about um especially, you know, some of those um that one famous man who decided not to leave.

[00:07:25]>> Harry Truman. Yeah, do you do you know or can you share more about the lead up to the uh the explosion or uh or the eruption and then the following eruptions and kind of that lead time that, you know, experts were giving residents um in the area and how that all went down. Yeah. So, everybody, you know, the Cascade Volcano Observatory is headquartered in Vancouver, Washington, up here in Southwest Washington. They've been monitoring all the Cascade volcanoes, I think since around the 1960s or so.

[00:07:58]Don't quote me on that, but they were there in 1980. And they noticed seismic activity building up in the month of March of 1980.

[00:08:09]And so they put more seismometers up there and the the infamous David Johnston, who is a volcanologist with the USGS, um he was the main or lead volcanologist that was just north of there. And unfortunately, you know, he lost his life on what's now called Johnston Ridge, where the observatory is, the closest one to the mountain.

[00:08:31]Unfortunately, you can't get access to it right now cuz the road washed out a couple winters ago. But they began really actively monitoring it. By April, a vent opened at the top of the cone, the cinder cone essentially.

[00:08:45]And it was a small little crater at the top. It put out some ash, nothing too crazy. But by mid-April, a noticeable bulge on the north-facing slopes.

[00:08:57]Again, pre-eruption it was 9,677 ft. After the eruption, around 8,300. So it lost the top 1,300 of the mountain.

[00:09:07]Well, that bulge on the north side was beginning to concern David Johnston and all of the volcanologists who were up there. People came from all around the world knowing that this was going to build to something. So the Forest Service put up what's called the red zone around the mountain, and you couldn't get it. It's technically the mountain is in Skamania County, just outside of the Cowlitz County line. Um and they couldn't necessarily keep people from sneaking in, and a lot of people did, and 57 people lost their lives that morning. but it So, this was well uh basically in like a television or meteorological world, this was a good forecast. It was well forecast. They knew this was going to happen. I don't think they estimated the power it was going to unleash, or they would have put people back even further, cuz it decimated everything to the north for about 8 mi. And uh David Johnston was about 4 and 1/2 to 5 mi north. And Harry Truman, who was the little old guy down at Truman's Lodge, or uh Spirit Lake Lodge, right on the uh lake, unfortunately, uh you know, he probably had a minute to live. It was a very fast eruption. Uh I want to go back to that lava dome picture you just had there. Um after the eruption, uh there was lava, and that's what you see in the foreground back there. Okay. Or in the background, I should say. Uh that was a lava dome. It grew to around 800 uh feet or so, and then after each subsequent eruption, May 25th, June 12th, July 22nd, that would blow away, and then a new one would form. And that ultimately, it'll take about 150 years or so, will slowly create another cone, and basically rebuild the top of the volcano, because it erupted uh in about 1857, I believe.

[00:10:54]And so, here it was another 130 years before it erupted in 1980.

[00:10:58]It's just incredible how much knowledge you have of this stuff, too. Like you labeled um the height of the volcano before and after to the T, Steve. So, I commend you on all of that knowledge. I ate I ate, slept, and breathed uh Mount St. Helens. I want I turned on I turned on KOIN 6 every night. Yeah, and watched our predecessors uh do the weather forecast, Dr. John Walls and Phil Volker, uh Chuck Wise, and they would tell us where the ash was going and that's it was it was truly the most fascinating event to happen in any of our lifetimes up here in the Pacific Northwest for sure.

[00:11:43]>> Definitely. I know people from, you know, across the country were seeing ash.

[00:11:48]Uh can you talk about that ash plume? I know it, you know, it it it uh it caused complete darkness in Spokane.

[00:11:56]Um that plume uh it spread across the US in 3 days and circled the earth in 15 days. Correct. Yeah, that's the my the 1980 eruption lasted about 9 to 10 hours continuously. So all day.

[00:12:12]Uh and that ash plume went to the north and east. So right up, you know, I guess luckily it went kind of right up the spine of the Cascades. So the least population possible and then ended up going out over Eastern Washington, Ritzville, Yakima, Spokane and it turned mid-daytime, you know, 12 noon into what looked like 12 midnight. Cars couldn't run, you know, we're talking about old carburetor cars.

[00:12:37]Nothing like today's technology.

[00:12:39]Uh and that ash plume, yeah, spread all the way out. They had physical traces of ash as far as Oklahoma and especially in Montana. There was also the explosion. Nobody heard it in the Portland area cuz that sound was all traveling to the north and east as well.

[00:12:56]So people in Montana heard what sounded like a sonic boom or a rumble when it first blew. But yet here 45 miles away we couldn't hear anything and yeah, that did travel the earth a couple of times and they were detecting uh sulfur dioxide in the atmosphere for about another year and a half after that. So but on a geological scale this mountain was nothing compared to Mount Mazama which was a Crater Lake.

[00:13:27]Mhm.

[00:13:28]Yeah.

[00:13:29]Yeah, Krakatoa, Pinatubo, uh you know, out in Wyoming. You know that one, you know, so >> Oh, the the mega the mega Yellowstone volcano or collection of volcanoes out there. Yeah, so you're saying even though this was a giant eruption for us on the scale of volcanoes, it's actually pretty small. One of the smaller ones.

[00:13:53]Yeah. Think about that for a second.

[00:13:55]Yeah, I know. I'm trying to I'm trying to right now. It's pretty incredible.

[00:13:59]>> [laughter] >> Yeah, and it and if it had blown out the south side, it would have decimated all of the reservoirs up there, Merwin, Swift, and Yale reservoirs that were created by the Army Corps of Engineers around World War II to generate hydrological power.

[00:14:14]>> Mhm. Um probably would have done significant uh damage to Yacolt, Amboy, maybe even down to Battle Ground. And now we're talking about population centers, you know, uh back then Clark County had about 200,000 residents in 1980 and of course now we're pushing 600,000. And but yeah, it was unfortunately, I never got to see the picture behind me. Mhm. But lots of friends and family would go up there.

[00:14:41]This is from 1978.

[00:14:43]Crystal clear blue water. Ice cold fresh mountain glacial water.

[00:14:49]Uh and unfortunately, all of that when it was superheated and melted instantaneously created these massive mudflows down the Toutle. It took out everything, every bridge, every house, the Weyerhaeuser complex with all of their um Caterpillars, you know, all the big heavy machinery. Just threw it like it was toys. And those are called lahars.

[00:15:11]Those flows of sediment, ash, rock, um just very explosive. And then when it melts the glaciers, um it creates those like mudflows. And that is kind of our biggest risk here for our other active volcanoes or if we were to see another eruption would be these lahars that just coat and fill these valleys and they travel long distances.

[00:15:37]Yeah, it just >> Toutle River to this day about 12 ft deep in most locations.

[00:15:41]>> Yeah.

[00:15:43]So, I was curious about the noise of the eruption. You were saying you couldn't hear it because it blasted to the north or do you remember hearing the boat?

[00:15:53]Nope.

[00:15:54]Uh that that was all residents in Portland, Vancouver did not hear it simply because the trajectory was out at about a 45° angle and up to the northeast.

[00:16:05]So, and it kind of the audio wave, the shock wave so to speak, kind of went up and over most eastern Washington cities, but then as you go further east, people started hearing it in uh other points of eastern Washington, northeast Washington, and certainly in Montana at elevated heights in Montana, people heard it there as well. So, pretty fascinating. That's several hundred miles away. Yeah, 4 5 600 miles over to the east.

[00:16:32]>> You know, this photo here is one that I took from a small uh Piper Comanche plane um or like a Cessna. Um I got to fly around it from um with one of our old co-workers um Scott and Scott Brock. He's a private pilot. And so, he took me up and we zipped around um Mount Hood and Mount St. Helens, but it was really cool to see the crater. And I um do you know if this is looking from the south or from the north? It's from the south, right?

[00:17:02]No, this is uh you'd be looking southeast, so you'd be on the northwest side of the volcano.

[00:17:07]>> we were north and you can see the cutout of That's the Toutle River. And that the Toutle River is still there, but that part of the Toutle River if you were to get right down in the crevasse of that creek or river, I should say, uh that's about uh about a 150-ft ledge down to the water. Wow.

[00:17:26]>> Yeah, that's that's on the northeast side looking back looking back looking back more uh south-southwest into the crater and that be over Windy Ridge cuz you can access the volcano from Skamania County. You got to go up the Columbia River Gorge and then head north up uh what's called Forest Road 99 and it goes to a spot called Windy Ridge and that I'm guessing is From the south.

[00:17:51]Yeah, southwest side. Just coming back around what you see in the foreground there is looking off to the north.

[00:17:56]But yeah, and it's tilted, you know, it's not up like this. It blew like that. So Yeah, it just blew its its hat right off the side.

[00:18:07]>> [laughter] >> Yeah. Incredible. And um I did have the um the time to climb to the top of Mount St. Helens. I've been up there twice.

[00:18:18]Um this was back in 2021. I took our then sports reporter AJ with me and we brought up a coin a coin flag, but um it was a beautiful day and this is such a big recreational area now. Have you ever hiked it um in the summer or the winter?

[00:18:35]Funny, I haven't, but I know a lot of people that have.

[00:18:39]Steve, we got to get you up there. I know. And I'm a big hiker, too. But that's >> [laughter] >> that's hiking right there.

[00:18:44]>> This is hiking. Yeah, we did like a an early morning alpine start at 2:00 a.m.

[00:18:49]to get up there near sunrise and yeah, you can see into the crater. You can see a ton of peaks around you. Um you know, Mount Adams, Mount Rainier, Mount Hood, and even like Jefferson. Yep. Um Before we wrap this up, I do want to talk about kind of the monitoring that's done now. Um you know, if we were to experience something like this again because Mount St. Helens is still an active volcano. You know, the likelihood that we see a big eruption just in our lifetimes after already seeing what I feel like is just so statistically low.

[00:19:25]Um but statistics also don't play into just natural, you know, geological phenomena that happens. Um so I Do you know much about the volcano observatory, some of the seismometers in the the tracking and monitoring that they do now? Yeah. Uh in fact, Larry Maston, who's a volcanologist with the USGS, uh he works out of Vancouver and he's come and presented to the American Meteorological Society before just on this subject matter. And their observatory is open to the general public. It's in Vancouver on the east side of Vancouver, east of 205, Cascade Park area. And you can actually see through the glass windows if they still have them there, uh of the seismometers on all of the major peaks.

[00:20:14]And uh it is headquartered right here in Vancouver where where I live. And it's really fascinating. Uh I would encourage um folks to reach out to the USGS and ask if there's an opportunity maybe before a classroom visits and stuff like that.

[00:20:29]But they're actively actively monitoring every single one of those volcanoes. And the University of Washington also has their own network um that constantly monitors. Uh it's Mount Rainier and Mount Hood that's most fascinating to me. Those ones have the the propensity to erupt next and perhaps the South Sister, I think it is, of the Three Sisters. That's growing at a rate of about, I think it was around an inch every year too. Don't quote me on that, but now that seems like not much, but that's pretty significant in geological that Keep in mind, Mount St. Helens, that bulge was growing at about a at one point 100 ft a day. Wow. Yeah.

[00:21:16]>> Right before it blew, it really I mean, you could visibly see it. And the the interesting fact about Mount Mount St. Helens is that the eruption was triggered by an earthquake, which triggered the landslide, which triggered the eruption. So, I don't know if we would need some sort of forcing like that, like Yeah. whenever we get an earthquake, and it might be more inland closer to the Cascades, I get a little bit concerned, just because of the history with Mount St. Helens.

[00:21:42]>> Yeah. Um but I don't Go ahead. I was saying that may not always be the case for an eruption to happen.

[00:21:48]>> [laughter] >> That 5.1, you're right. You're right.

[00:21:51]That 5.1 earthquake that led up to the landslide and then the explosion, it was all based on the amount of pressure building underneath the volcano, which was increasingly was increasing rapidly in the month of uh April and then the first half of May.

[00:22:07]Uh I wanted to mention uh one other thing that uh when that blew uh on May 18th, 1980, it I was going to say [clears throat] something about I lost my train of thought. Kelly, don't get old. Uh it it had something to do with the eruption itself and what triggered it on uh May 18th.

[00:22:26]Um oh, uh subduction. So, we have the continental plate, we have the Juan de Fuca plate, and the Juan de Fuca plate subducts underneath the continental North American plate. That's why [clears throat] we have um sort of our version of the Ring of Fire on the West Coast in the Cascade Range is built on that subduction of the Juan de Fuca plate underneath the plate tectonics underneath the North American plate. And that right there is 1980, May 18th, 1980.

[00:22:56]Unreal. You know, we only have a Oh, say, we only have a couple minutes left, but um just going back to, you know, what we do about our volcanoes now. It is nice that we still have this massive network of monitoring um and also volcanologists and seismometers on these craters and rims of a lot of our active volcanoes and there's a number of them. All of our strato volcanoes, the big ones in Washington, are active. Um Mount Hood is also active, the Three Sisters are active, same with Jefferson. So, it is um something that we will continue to watch throughout our lifetimes, you know, just to to see if there is any change or rapid growth and you know, it it it's probably hard to forecast a volcano, but there will be, you know, some lead time Oh, yeah.

[00:23:47]>> Um and notice because of these these instruments and monitors that are out there. So, it is it is nice to have that comfort that there are really smart people and experts and scientists tracking our volcanoes on a daily basis.

[00:24:01]Yeah, a lot of uh observation points on all of those volcanoes. It's just not one seismometer on each volcano. They have dozens and dozens on Mount St. Helens and will in perpetuity. And I think um back in college at the University of Washington when I took my volcanoes class, I remember my professor saying, um you know, Mount Rainier and Mount Hood are the volcanoes to watch now. Um and if Rainier were to blow, he would he was saying that residents around those valleys probably have about 20 minutes to get a move on it. Um and of course, it would be there would be a lot of activity leading up to that moment, but it's just so interesting to kind of think about. It's like a movie playing in my head.

[00:24:43]And it's also, you know, a movie that you lived through with Mount St. Helens, Steve. So, I just find that so so fascinating and so exciting and um I'm so happy you were able to share uh your side of it when you were seven um as we ring in ring in the 46th anniversary of the eruption of Mount St. Helens.

[00:25:02]>> [laughter] >> Anything else anything else you want to add before we take off?

[00:25:07]Boy, yeah just keep an eye to the sky. You know, Mount St. Helens will erupt again at some point probably not in our lifetime to the extent it did 1980. That pressure's been released, but we can get eruptions again. It did erupt we were thinking we were going to get an eruption in I think it was summer of 2004 or 2005, but it didn't happen. So everybody flocked up to those ridges, got their you know, TV cameras and satellite trucks ready and it just went back to sleep. So we wait and watch.

[00:25:38]Well, I think the the three big takeaways are that yeah, the size of the eruption likely won't happen in our lifetimes, but we do live by nine or so active volcanoes and they are being monitored very well by experts. So you can rest easy.

[00:25:57]Yeah, especially Mount Rainier that's Yeah, the valley coming down to Orting that's sort of the area that they're most concerned with.

[00:26:06]But they have evacuation plans in place, too. Exactly.

[00:26:09]Um all right. Well, that's going to wrap it up for us Steve. Thank you so much for giving us your expertise on the big eruption of Mount St. Helens 46 years years ago was a big day here around the region.

[00:26:22]>> [laughter] >> Yeah, it was.

[00:26:23]All right. We'll catch you next time.

[00:26:25]Yeah.