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Subject: Archive: Mt. St. Helens erupts, May 18, 1980


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Around 57 people killed
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Date Posted: Monday, May 18, 02:30:43pm

On March 27, 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. Helens in Skamania County, U.S. state of Washington. It initiated as a series of phreatic blasts from the summit then escalated on May 18, 1980, as a major explosive eruption. The eruption, which had a Volcanic Explosivity Index of 5, was the most significant to occur in the contiguous 48 U.S. states since the much smaller 1915 eruption of Lassen Peak in California. It has often been declared the most disastrous volcanic eruption in U.S. history. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope.

An earthquake at 8:32:11 a.m. PDT on Sunday, May 18, 1980, caused the entire weakened north face to slide away, creating the largest landslide recorded. This allowed the partly molten, high-pressure gas- and steam-rich rock in the volcano to suddenly explode northwards toward Spirit Lake in a hot mix of lava and pulverized older rock, overtaking the avalanching face.

An eruption column rose 80,000 feet (24 km; 15 mi) into the atmosphere and deposited ash in 11 U.S. states and significant ash in two Canadian provinces. At the same time, snow, ice and several entire glaciers on the volcano melted, forming a series of large lahars (volcanic mudslides) that reached as far as the Columbia River, nearly 50 miles (80 km) to the southwest. Less severe outbursts continued into the next day, only to be followed by other large, but not as destructive, eruptions later that year. Thermal energy released during the eruption was equal to 26 megatons of TNT.

Approximately 57 people were killed directly, including innkeeper Harry R. Truman, photographers Reid Blackburn and Robert Landsburg, and geologist David A. Johnston.
Hundreds of square miles were reduced to wasteland, causing over $1 billion in damage (equivalent to $3.4 billion in 2019), thousands of animals were killed, and Mount St. Helens was left with a crater on its north side. At the time of the eruption, the summit of the volcano was owned by the Burlington Northern Railroad, but afterward the land passed to the United States Forest Service. The area was later preserved, as it was, in the Mount St. Helens National Volcanic Monument.


https://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens

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Replies:
Subject Author Date
I believe this was the only time in history a volcano killed people in the US (NT)Please correct me if I'm wrongTuesday, May 19, 01:16:45pm
Every year I tell my experience: I was a senior in high school and went out on my balcony and saw the explosion. (NT)MoreCowbelleWednesday, May 20, 02:27:41am
One of the more compelling TV specials on the event, was 2018's PBS' "We'll Meet Again" with people's personal reflections of that day, and one woman's story searching for her ranger pilot who saved her four decades earlier. ...Another story was a young government geologist living near the mountain to monitor, died that day.Wednesday, May 20, 03:49:57am


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