Mt. St. Helens Eruption: 30th Anniversary

Eruption forever altered landscape, knowledge of volcanoes

On Sunday, May 18, 1980 at 8:32 a.m., the bulging north flank of Mount St. Helens slid away in a massive landslide -- the largest in recorded history. Seconds later, the uncorked volcano exploded and blasted rocks northward across forest ridges and valleys, destroying everything in its path within minutes.

Nine hours of explosive volcanic activity ensued, altering the landscape, and what we know about volcanoes, forever.

The opening minutes of the eruption claimed the lives of 57 people. Prevailing winds carried 520 million tons of ash eastward across the United States, producing darkness during daylight hours in Spokane, more than 250 miles away, and other communities is its path. Water from melting snow and ice mixed with loose rock debris to form lahars – volcanic mudflows – that poured down river valleys ripping trees from their roots and engulfing roads, bridges and houses.

Thirty years later, excess sediment is still moving down those river drainages most affected by erupted debris on May 18, impressing upon all that hazards can persist long after an eruption is over. The eruption left an indelible effect on the regional economy and lives of citizens in the Pacific Northwest and beyond.

“The spectacular nature of the May 18, 1980 eruption is one of those unforgettable time markers for anyone who lived through the effects of the eruption or saw the images through the media,” said Carolyn Driedger, hydrologist and outreach specialists at the Cascades Volcano Observatory. “Thirty years later, people still want to tell you where they were and what they experienced when Mount St. Helens blew. In the Pacific Northwest and around the world, people awoke to the idea of what it meant to live near an active volcano.”

The eruption of Mount St. Helens -- the most destructive eruption in U.S. history -- was the first large explosive eruption in the United States since the advent of modern volcanology. It was a catalyst for an era of unprecedented scientific discovery, monitoring development and community awareness.

The volcano instantly became, and remains, a volcanologist’s ideal laboratory. Its accessibility has allowed scientists to return to the volcano over and over again to examine new deposits before they eroded away, to test new concepts about how volcanoes work, and to try out new tools. The landslide exposed the inside the mountain affording scientists with an unprecedented opportunity to inspect a volcano’s interior, and learn about its history from the inside out.

Frequent eruptions have helped scientists draw correlations between monitoring signals and impending eruptions.


Mount St. Helens: May 18, 1980



Mount St. Helens: Catalyst for Change

“Since the numerous eruptions of Mount St. Helens in the 1980s, volcano monitoring has come a long way,” said Seth Moran, an earthquake specialist at CVO. “In many locations, we’ve essentially gone from having a few instruments placed on a volcano’s flanks to having a broad network of earthquake and deformation monitoring devices feeding us information 24/7. While we’re not able to do this on every volcano, where we can, these instruments have given volcanologists unprecedented access to what’s really happening on a volcano, and help greatly in predicting the nature of future activity.”

USGS Link

________________________________
ed: to fix a link.

[edit on 15-5-2010 by LadySkadi]

PATH OF DESTRUCTION: The Lateral Blast
The speed and force with which Mount St. Helens exploded is evident in the varying degrees of devastation wrought over 19 miles northwest of the crater.
[atsimg]http://files.abovetopsecret.com/images/member/2e91248692f4.jpg[/atsimg]


DIRECT BLAST ZONE
Reach: About 8 miles from summit
Force: Shockwave travels horizontally over the area at speeds above 670 mph. Pyroclastic flows of gas and rock, reaching up to 800 degrees, race down the mountain at speeds up to 200 mph.
Impact: Everything in the direct blast zone -- natural or manmade -- is obliterated within seconds. Nothing, not even the topography of the zone, could deflect the flow of material carried by the blast.

4 miles from summit: Within 90 seconds, the avalanche reaches Spirit Lake and Harry Truman's lodge is buried by several hundred feet of mud. Truman, 83, is never found.
[atsimg]http://files.abovetopsecret.com/images/member/037f39c78740.jpg[/atsimg]

6 miles: The blast reaches David A. Johnston, 30, a U.S. Geological Survey volcanologist, killing him as he warns on his radio: "Vancouver, Vancouver! This is it!"
[atsimg]http://files.abovetopsecret.com/images/member/3dc2acffbc05.jpg[/atsimg]

7 miles: Newspaper photographer Reid Blackburn, 27, is killed sitting in his Volvo at Coldwater Camp. He was covering the volcano for The Columbian in Vancouver, Wash., and National Geographic.
[atsimg]http://files.abovetopsecret.com/images/member/b0bf7f26c4b2.jpg[/atsimg]

INTERMEDIATE BLAST ZONE
Reach: 9 to 17 miles from summit
Force: Direction and force of shockwave are evident in patterns of flattened trees.
Impact: Some people caught in zone survive. About 4 million board feet of timber topples.

9 miles from summit: Four loggers are hit at Elk Rock. Three die from severe burns after being rescued.

12 miles from summit: The entire Seibold family -- Ron, 41, a state employee; Barbara, 33, an Olympia High School teacher; and their children, Michelle, 9, and Kevin, 7 -- die in their Chevy Blazer near Camp Baker, when the hot blast explodes through the Toutle Valley.

12 miles: Eight peole die at Camp Baker trying to flee hot mudflows traveling as fast as 30 mph that toss logs, trees and even a locomotive like toys. The wall of mud buries rivers, forests and people up to 17 miles from the summit.
[atsimg]http://files.abovetopsecret.com/images/member/b0bf7f26c4b2.jpg[/atsimg]


SEARED ZONE
Reach: 17 to 19 miles from summit
Force: Heat is still strong enough to singe trees.
Impact: Trees are killed but left standing. (1)


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ed: fix insert

[edit on 16-5-2010 by LadySkadi]

Thanks for the reminder, the info and the vids. I'll always remember the stills of the mountainside blowing away, it's etched into my memory!

The awesome power of mother earth never ceases to amaze!

Anyway, thanks for this, S+F

Exactly on my birthday, born 2 years before the eruption.

One of the most spectacular eruptions documented I think.

Etched in memory, for me too. I was in grade school at the time, but I remember I was playing outside, the day was gorgeous, blue sky, perfect views of Mt. Hood and Mt. St. Helens from our front yard. The view of the ash cloud was amazing! and confusing. As a kid, I had no idea what was going on. Remember running into the house to tell my dad something was wrong with the mountain - by then, of course, it was all over the news.








[edit on 16-5-2010 by LadySkadi]

I just watched the NOVA special - Definitely recommended.

NOVA: Mt. St. Helens: Back From The Dead
30 years after the massive eruption...could it happen again?

PBS video episode, watch online









[edit on 16-5-2010 by LadySkadi]

Excellent thread OP. S&F for you.

I wasn't alive yet for the eruption, but I have watched a lot of the news footage and coverage. It's amazing to me all of the changes that have taken place in the land because of this one day. It kinda makes me feel a little small in the entire scheme.. I like that. Just being alive to experience the sometimes mundane is a gift we overlook.

Thanks for the reminder.

Great job and info provided.

I was 40 miles outside of Spokane when it happened. Like a previous poster said, it WAS a beautiful day. Spring. May. I was 5 years old. A Sunday. I played Hopscotch with my younger sister that afternoon.

It got dark early. You could see the blackness roll in from the West. Later it was light again, when the ash fell. It was like snow, but definitely not like snow. A fine white dust falling everywhere.

In the weeks following, we were required to wear masks to go play outside. Yes, to go play outside...

And life went on...

SpeedBump

reply to post by LadySkadi


I remember the eruption of Mount St. Helens because I was 7 years old.

Quote from : Wikipedia : Mount St. Helens

Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States.

It is 96 miles (154 km) south of Seattle and 50 miles (80 km) northeast of Portland, Oregon. Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century.

The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that includes over 160 active volcanoes.

This volcano is well known for its ash explosions and pyroclastic flows.

Mount St. Helens is most famous for its catastrophic eruption on May 18, 1980, at 8:32 am PDT which was the deadliest and most economically destructive volcanic event in the history of the United States.

Fifty-seven people were killed; 250 homes, 47 bridges, 15 miles (24 km) of railways, and 185 miles (298 km) of highway were destroyed.

The eruption caused a massive debris avalanche, reducing the elevation of the mountain's summit from 9,677 ft (2,950 m) to 8,365 ft (2,550 m) and replacing it with a 1 mile (1.6 km) wide horseshoe-shaped crater.

The debris avalanche was up to 0.7 cubic miles (2.9 km3) in volume.

The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied.

As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits.

The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted.

The largest of the dacite domes formed the previous summit, and off its northern flank sat the smaller Goat Rocks dome. Both were destroyed in the 1980 eruption.

It was one year directly after having been through my first hurricane, at age 6, Hurricane David, in 1979, in Florida, so I remembered vividly the talk about it.

Barely being able to understand the concept of a hurricane, until after it, the events of a volcano erupting definitely sunk into my psyche deeply and forever.

CBS News on the Eruption of Mt St Helens - May, 1980!


Volcano's are one of the most destructive forces on the planet Earth.

My uncle who lived in Washington when this happened sent me some ash samples. 3 different types. One was what many think of when you would think of as ash. The second one was almost like sand. The third sample was almost like salt and pepper mixed.


Those 3 samples were taking from the town he lived in at the time.

Mt St Helens: A Look Back

OPB

Watch videos from OPB's coverage of Mount St. Helens before and after the eruption.



[edit on 17-5-2010 by LadySkadi]

Interview with Harry Truman -
"I will stay right here and watch it" when asked what he would do if the mtn. erupts.




Cheesy song - but still...




[edit on 18-5-2010 by LadySkadi]

Respect to the Mountain and Mama Nature...

Peace

Originally posted by LadySkadi
Respect to the Mountain and Mama Nature...

Peace

Yeah well at least the US Government came through during that crises!


6 months after the fact, the town my uncle lived in received a huge shipment of those paper dust masks. Paid for by the US tax payer.




[edit on 18-5-2010 by SLAYER69]

I was 16 when a good chunk of that mountain decided to go walkabout... I was about 35-40 miles from the main path of the ash cloud, just south of it. It was one of the most awe inspiring things I've ever seen...

We didn't get a whole lot of ash, just enough to see on a dark car.

Wow. Sometimes words are just not adequate.

reply to post by LadySkadi


God!

I Remember watching a news story on that guy on ABC. Everybody knew something was going to happen. You know, honestly I admired his attitude. In the end he probably had an awesome experience meeting his maker!

[I'm not trying to say I'm glad he is dead]

What I meant was, he knew the danger and let's face it, it must have been an incredible last few seconds of his life a lot better than wasting away in some old farts home!

Semper Fi

reply to post by SLAYER69
Truman - he reminds me so much of my own grandfather...

Much respect for a guy that lived and loved and went out on his terms.

reply to post by SLAYER69


Somehow I've always pictured him sitting on his porch, sippin' a beer as the cloud closes in.

worse ways to go, I suppose. On the mountain he loved.