Mount St. Helens eruption: What most people get wrong about the 1980 blast

It was a Sunday. May 18, 1980. Most people think the Mount St. Helens eruption was just a vertical explosion, like a cork popping out of a champagne bottle. It wasn't. It was a sideways collapse that basically rewrote everything geologists thought they knew about how volcanoes behave.

The mountain didn't just "blow up." It fell apart.

David Johnston, a volcanologist with the U.S. Geological Survey, was stationed on a ridge about six miles away. He was one of the first to see it. He keyed his radio and shouted, "Vancouver! Vancouver! This is it!" Those were his last words. The ridge he was standing on—Coldwater II, now known as Johnston Ridge—was scrubbed down to bedrock seconds later.

Honestly, the sheer scale of the energy released is hard to wrap your head around. We're talking 24 megatons of thermal energy. That’s roughly 1,600 times the size of the atomic bomb dropped on Hiroshima.

The bulge that everyone saw coming

For months, the north face of the mountain had been growing a massive "bulge." Magma was pushing up into the volcano, but instead of coming out the top, it was getting stuck in the side. By early May, the north flank was sticking out by about 450 feet. It was growing five feet a day.

Everyone knew something was going to happen. The state had set up "Red Zones" and "Blue Zones" to keep people out, but there was a ton of political pressure to reopen the area for logging and recreation.

Then at 8:32 a.m., a magnitude 5.1 earthquake hit.

That earthquake was the trigger. It shook the weakened north face so hard that the entire side of the mountain just... slid away. This was the largest landslide in recorded human history. It moved at speeds up to 155 miles per hour. When that heavy "lid" of rock moved, the superheated water and magma inside suddenly had nothing holding it back. It flashed into steam instantly.

The mountain basically uncorked sideways.

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The lateral blast and the "Stone Wind"

Because the eruption went sideways (a lateral blast), it caught people by surprise. The blast zone covered 230 square miles. It didn't just burn trees; it snapped them like toothpicks.

Huge Douglas firs, some over 100 years old, were knocked down in neat rows. If you go there today, you can still see the "Blowdown Forest." It looks like a giant took a comb to the mountainside. Closer to the crater, in the "Removal Zone," there was nothing left at all. No trees. No soil. Just grey ash and pumice.

The heat was intense.

In some areas, the "stone wind"—a mix of hot gas and pulverized rock—was moving at 670 miles per hour. That’s nearly the speed of sound. You can’t outrun that. You can’t even drive away from it.

People like Robert Landsburg saw it coming and knew they wouldn't survive. Landsburg was a photographer who spent the last seconds of his life rewinding his film, putting his camera in its case, and lying on top of it to protect the images. His photos survived. He didn't.

The misconceptions about the death toll

People often ask why 57 people died if the government had set up evacuation zones.

Here's the reality: Most of the people who died were actually outside the restricted Red Zone. The "safe" areas weren't actually safe because no one had ever seen a lateral blast of this magnitude before. Scientists expected a vertical plume, not a 300-mile-per-hour wall of hot ash moving horizontally.

Harry R. Truman is the guy everyone remembers. He was the 83-year-old owner of the Mt. St. Helens Lodge at Spirit Lake. He refused to leave. He’d lived there for 50 years and said the mountain was a part of him. He’s still there, buried under 150 feet of landslide debris and lake water.

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But there were others. Campers, loggers, and photographers who thought they were at a safe distance.

The ash was the real killer for those further away. It didn't just stay in Washington. Within three days, the ash cloud had crossed the U.S. Within 15 days, it circled the globe. In Yakima, Washington, it got so dark in the middle of the day that the streetlights turned on and the birds stopped singing because they thought it was night.

What the mountain looks like now

If you visit today, you’ll see that the Mount St. Helens eruption didn't leave a dead landscape. It left a laboratory.

Ecologists were shocked at how fast life came back. They thought it would take centuries. Instead, it took weeks.

• Pocket gophers survived in their underground burrows. When they dug their way out, they mixed fresh soil with the ash, helping seeds take root.
• Lupines were the first flowers to really take over. They are nitrogen-fixers, meaning they could grow in the nutrient-poor ash and actually "fix" the soil for other plants.
• Spirit Lake is still covered in thousands of floating logs from 1980. They move around with the wind, a giant carpet of dead timber that supports a brand new ecosystem of aquatic life.

The crater itself is now home to one of the world's youngest glaciers. While most glaciers globally are shrinking, the "Crater Glacier" inside Mount St. Helens is actually growing because the crater walls shade it from the sun.

Why we should still be watching it

Mount St. Helens is not dead. It’s "recharging."

Between 2004 and 2008, the volcano woke up again. It didn't explode, but it pushed out a series of lava domes that looked like giant "whalebacks" of rock. It was a slow, steady oozing of thick dacite lava.

The USGS (United States Geological Survey) keeps it heavily wired. There are seismometers, GPS stations, and gas sensors everywhere. We can now measure the mountain "breathing." When magma moves deep underground, the whole mountain expands by millimeters. We can see that in real-time now.

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Is it going to blow again? Yes.

Will it be like 1980? Probably not. The 1980 event was so big because the north flank collapsed. Now that the side of the mountain is already gone, future eruptions are more likely to be vertical or just slow lava flows. But in geology, there are no guarantees.

Actionable insights for visiting or studying the blast

If you’re planning to head out there to see the aftermath of the Mount St. Helens eruption, don't just go to the first viewpoint you see.

First, hit the Johnston Ridge Observatory. It’s the closest you can get without a hiking permit. You get a direct line of sight right into the "throat" of the volcano. You can see the lava dome and the breach where the mountain fell away.

Second, check out the Ape Cave on the south side. This wasn't formed in 1980—it’s a lava tube from an eruption about 2,000 years ago. It gives you a sense of the long-term history of the area. It’s dark, cold (42 degrees Fahrenheit year-round), and requires a reservation now.

Third, if you want to climb to the summit, you need a permit. They are hard to get and go on sale months in advance. It’s a grueling hike through loose ash—kinda like walking up a sand dune for five hours—but standing on the rim is wild.

Finally, remember that the volcanic ash is basically tiny shards of glass. If you're looking at old equipment or ruins in the area, don't kick up the dust. It’s bad for your lungs and even worse for car engines.

The 1980 event changed how we monitor every volcano on Earth. It taught us that mountains aren't static. They are dynamic, slightly terrifying, and incredibly resilient.

Essential Next Steps for Travelers and Students

1. Check the USGS Volcano Hazards Program website for the current alert level before visiting. It is almost always at "Green" (Normal), but it’s good practice.
2. Book Ape Cave and Climbing permits via Recreation.gov. For the summer months, these often sell out the moment they are released (usually in February or April).
3. Visit the Forest Learning Center on the way up to the ridge. It’s free and offers the best explanation of how the timber industry recovered and replanted millions of trees in the wake of the blast.
4. Prepare for no cell service. Once you start climbing into the Gifford Pinchot National Forest, your GPS will likely fail. Download offline maps of the Toutle River valley and surrounding trails.
5. Look for "Ghost Lake." It’s a lesser-known spot where you can see trees still standing underwater, preserved by the cold and the unique chemistry of the post-eruption environment.