Copyright © 2001 The Seattle Times Company
Local News : Sunday, May 14, 2000
Timeline of Mount St. Helens activity
by Eric Sorensen
Seattle Times science reporter
1978 - United States Geological Survey geologists Dwight Crandall and Donal Mullineaux warn that Mount St. Helens has been "more active and more explosive during the last 4,500 years than any other volcano in the contiguous United States."
March 15, 1980 - After a five-year period in which the mountain had 44 earthquakes, Mount St. Helens enters a week in which more than 100 are recorded.
March 20 - A magnitude 4.2 quake just north of the summit triggers avalanches on the mountain.
March 21 - Seismologists suspect the mountain is about to have its first eruption since 1857 but are reluctant to say so publicly.
March 24 - The mountain experiences as many as 20 earthquakes an hour.
March 25 - Five earthquakes greater than 4.0 occur in one hour. Forest Service officials close the Spirit Lake Information Center, access to the mountain above the tree line and several roads leading to the mountain. The FAA imposes flight restrictions near the volcano. A large crack appears in the snow on top.
March 27 - Earthquakes become more frequent. A hole in the summit icecap appears, followed by a loud boom, ash and smoke, a 4.7 earthquake and a 7,000-foot-tall black plume. A 200-foot-wide crater is left behind.
Hundreds of loggers, Forest Service employees and residents are evacuated from a 1.5-mile radius. To accommodate flooding and mudflows, Pacific Power and Light begins drawing down three reservoirs on the south side of the volcano.
March 28 - A dozen more eruptions take place.
March 30 - Ninety-three explosions take place in one day. As many as 70 aircraft are seen flying around the mountain at one time.
March 31 - Cowlitz County Commissioners declare a state of emergency. Cabin owners start complaining about being kept from their retreats.
The Longview Daily News quotes lodge owner Harry R. Truman as saying, "I think the whole damn thing is overexaggerated. . . Spirit Lake and Mount St. Helens are my life. . . . You couldn't pull me out with a mule team."
April 1 - Explosive plumes of steam and ash reach 20,000 feet. Scientists begin to anticipate the explosion of magma, the molten rock welling up from deep within the Earth. Three hundred loggers return to work northwest of the volcano.
April 3 - Summit crater is now 1,500 feet wide and 300 feet deep.
April 8 - A series of explosions lasts four hours, the longest yet.
April 19 - Scientists notice that the mountain's north flank is bulging outward.
April 25 to May 15 - Explosions subside, resume and subside again.
May 17 - Bulge continues to grow five feet a day. USGS Geologist David Johnston replaces Harry Glicken at a monitoring station five miles north of the mountain.
May 18, 8:32 and 20 seconds a.m. - A 5.1 earthquake takes place one mile beneath the volcano. Rock and ice slide into the crater.
8:32 and 21 seconds - The bulging north flank begins to ripple, churn and slide away in blocks. A giant debris avalanche approaches speeds of 180 mph.
8:32 and 45 seconds - A huge explosion blasts out from where the north face slid.
8:33 - The volcano, which one geologist calls a superheated champagne bottle shaken for two months, is uncorked. A lateral blast of rock, ash and hot gases heads northward.
8:33 and 20 seconds - The blast increases to nearly supersonic speed and overtakes the debris avalanche, burying Truman and 20 or so summer homes along the North Fork of the Toutle Valley. Within an eight-mile radius, virtually everything is obliterated or carried away. Inside this zone is Johnston, whose famous last radio transmission was: "Vancouver! Vancouver! This is it!"
8:34 - Within a 15-mile radius, everything is flattened. Enough timber is blown down to build 300,000 two-bedroom homes.
Eight miles from the blast, Buzz Smith and his sons Eric and Adam, then 10 and 7, watch trees blow down around them. They are covered in cold, wet ash, followed by another, superheated layer of ash. They later began trekking out by compass.
Along the Green River, 13 miles from the blast, Terry Crall and Karen Varner, both 21 of Longview, and Bruce Nelson, 22, and Sue Ruff, 21, of Kelso are engulfed in burning rubble. Crall and Varner are killed. Nelson tells Ruff that, if they survive, he will marry her. They do; he does. They have since divorced.
Fifty-seven people die, mostly by suffocating on hot ash. They are the first recorded fatalities from volcanic activity in the continental United States.
8:35 a.m. - Mudflows of volcanic debris and water begin on Pine Creek, Muddy River, Swift Creek, the Kalama River and the South Fork of the Toutle River.
8:47 a.m. - A vertical column of ash and steam rises in a mushroom cloud 12 miles above the volcano. The cloud generates lightning.
10 a.m. - Ash cloud has reached Yakima. Darkness-sensitive street lights turn on.
11:45 a.m. - Ash cloud has reached in Spokane.
1 p.m. - Mudflows begin in the North Fork of the Toutle River as water-saturated parts of the avalanche begin to slump and flow. More than 65 million cubic yards of sediment are sent toward the lower Cowlitz and Columbia rivers. The Columbia River navigational channel is cut from 39 feet to 13 feet.
3 p.m. - Toutle River crests at 21 feet above normal.
5:30 p.m. - Eruption subsides after ejecting 540 million tons of ash.
7:50 p.m. - Smith and his sons are picked up by a rescue helicopter.
May 19 - Bathtub-ring mudlines across the region show mudflows were on average more than 60 feet deep. Ash cloud arrives in central United States.
May 25 - A less energetic eruption puts ash nine miles into the air, producing ash falls in southwestern Washington and nearby Oregon.
June 1 - After circling the globe many times, most ash settles out. Some of the smallest fragments remain suspended in the upper atmosphere for years.
June 12 - After several weeks marked by occasional steam and a nighttime glow from its crater, the volcano erupts again and forms a dome of lava on the crater floor.
July 22 - Several eruptions destroy most of the dome. The volcano continues to have periodic eruptions into 1984, with the dome rising more than 800 feet. At the current rate of growth, it will take a century for Mount St. Helens to reach its former height.
Eric Sorensen's phone message number is 206-464-8253.
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