Categorized | Featured, Sci-Tech, Volcano

Volcano Watch: A geologist remembers the Mount St. Helens eruption 37 years ago

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

Before the eruption of May 18, 1980, Mount St. Helens’ elevation was 2,950 m (9,677 ft). View from the west, Mount Adams in the distance. S. Fork Toutle River is the valley in the center of the photo. Photo taken 1979 courtesy of USGS.

Before the eruption of May 18, 1980, Mount St. Helens’ elevation was 2,950 m (9,677 ft). View from the west, Mount Adams in the distance. S. Fork Toutle River is the valley in the center of the photo. Photo taken 1979 courtesy of USGS.

The morning of May 18, 1980, was warm and sunny in southwestern Washington. At 8:32 a.m., I was in the room with seismographs that had been established in the Forest Service building in Vancouver, 70 km (45 mi) southwest of the volcano. Suddenly, needles on the seismographs wiggled furiously.

A startled colleague and I watched in amazement as the shaking continued. We realized that something catastrophic was happening at Mount St. Helens. I ran upstairs to radio David Johnston, a friend and colleague who was at an observation post (Coldwater 2) 10 km (6 mi) north of the volcano. Receiving no answer, I raced back downstairs. Though the shaking continued, no one could see the volcano from the building.

The Forest Service ordered a fire-spotter plane to investigate. About 30 minutes later, when it left Vancouver, I was aboard. A gray columnar cloud towered above a Mount St. Helens that had lost its top, no longer rising gracefully to a peak like Mount Fuji.

Aerial view of the May 18, 1980, eruption of Mount St. Helens as seen from the southwest. This column of ash and volcanic gas reached a height of about 18.2 km (60,000 ft).

Aerial view of the May 18, 1980, eruption of Mount St. Helens as seen from the southwest. This column of ash and volcanic gas reached a height of about 18.2 km (60,000 ft).

The plane reached the south side of the volcano but, because of ash in the air, couldn’t go farther north. Flying east and west for the next three hours, we observed, photographed, and wondered.

We had glimpses into the deep crater, around which the upper slope of the volcano was now only a shell. Radio messages told us of mudflows down the Toutle River valley that were threatening the I-5 bridge, but we could see nothing in the valley.

Nearly half a mile wide, the column of ash and volcanic gas rose from the crater to a height of more than 24 km (80,000 ft). The margin of the column was made of bulbous cells that convected internally while rising with the column. Within the column, lightning flashed.

Eerily, above the droning of the plane’s two engines, we heard nothing from the eruption—like watching a silent movie. Every so often, we saw small flows of ash overtop the crater rim and start down the south flank before stopping.

Around noon, the ash column, which had been gray, assumed a darker color. Its intensity increased and was almost frightening to us in the plane. Looking over the west crater rim, we saw pyroclastic flows moving northward onto what became known as the Pumice Plain.

Low on fuel, we returned to Vancouver around 12:45 p.m. I was replaced by another observer and returned to the Forest Service building, certain that David Johnston had perished.

USGS geologist Don Swanson (in red) and his colleague, Jim Moore, view a car filled with ash deposits from the May 18, 1980, eruption of Mount St. Helens.

USGS geologist Don Swanson (in red) and his colleague, Jim Moore, view a car filled with ash deposits from the May 18, 1980, eruption of Mount St. Helens.

Sometime in mid-afternoon, I debriefed Harry Glicken, a young geologist who had manned Coldwater 2, where Dave spent his final night. Harry had managed to get a seat on a search-and-rescue helicopter that wended its way up the North Fork Toutle valley. He noticed that the valley was floored by a hummocky debris avalanche deposit. (Harry eventually wrote his Ph.D. dissertation about the avalanche, showing that it formed when the upper north flank of the volcano slid away, opening the crater.)

The changed topography and murky viewing conditions kept Harry from finding Coldwater 2, where he had spent many days before Dave replaced him the night before. We huddled on an outside balcony for the private debriefing. Tears come to my eyes now, remembering how distraught Harry had been, thinking that if he could only have found Coldwater 2, he might have saved Dave. Days later, he finally accepted that Dave died within a minute after the eruption started.

Mt. St. Helens' glacier extent maps before and after May 18, 1980.

Mt. St. Helens’ glacier extent maps before and after May 18, 1980.

Later, I was able to call my wife in Cupertino, California. When she answered, I breathlessly blurted, “Barbara, I’m okay.” There was a long pause before a tentative, puzzled voice replied, “That’s nice.” Surprised by her lack of concern, I explained what had happened. She hadn’t had a radio or TV on all day, knew nothing of the eruption, and had been spared hours of concern.

Thirty-seven years ago. Fifty-seven dead. Thousands of lives altered. The volcano where I picnicked as a boy, and which I climbed as an adult, had turned nasty. The science of volcanology was changed forever, and today the risks from future eruptions anywhere in the world are lessened because of what happened on that fateful day.

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Jun 22, 2017 / 5:15 pm

 

 

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