Building to another eruption

In this May 18, 2016, file photo, contrails follow a plane as it passes by Mount St. Helens in the Gifford Pinchot National Forest. Now 40 years to the day that St. Helens erupted, the mountain remains the most active in the Cascade Range.

Editor’s Note: This originally ran in the March 24, 1985, edition of the Lewiston Tribune.

VANCOUVER, Wash. — David Johnston stepped off the helicopter at a parking lot at timberline on Mount St. Helens on March 27 five years ago, the first scientist to fly over the volcano’s summit since it had erupted several hours earlier.

“This is an extremely dangerous place to be,” Johnston told reporters who gathered round him. “If it were to erupt right now, we would die.”

As Johnston spoke, the still of the clear early spring afternoon was punctuated by the cracking of ice on the volcano’s glaciers and the rumble of avalanches caused by a week of intensifying earthquakes.

After 123 years of silence, Mount St. Helens was clearing its throat.

Johnston, 30, had survived the dangers of a restless volcano before. He and six others had spent five frigid nights on the flanks of an Alaskan volcano after their helicopter crashed. They were rescued only 12 hours before that mountain erupted in 1976.

The U.S. Geological Survey scientist spoke prophetically about the threats of Mount St. Helens. He spoke of superheated, glowing avalanches roaring down the sides of the volcano at speeds approaching 100 miles per hour. He told of devastating mudflows and hurricanes of ash.

“We’re standing next to a dynamite keg, and the fuse is lit,” said Johnston. “We just don’t know how long the fuse is.

“I am genuinely afraid of it.”

Two months later, Johnston died in the volcano’s cataclysmic eruption on May 18, 1980, blown off a ridge by a blast that approached with almost supersonic speed. His body has never been found.

Mount St. Helens remains the dynamite keg with an unpredictable fuse that Johnston described on that March afternoon five years ago.

Scientists are still unsure whether the eruptive cycle which began March 27, 1980, with that first, small eruption has run its course or whether the volcano could still explode with a fury.

The volcano has been virtually quiet for more than six months — the longest period of stillness since it reawakened. There are indications Mount St. Helens may have gone back to sleep and there are other indications, just as strong, that the volcano is still very much alive.

“We just can’t answer what comes next,” said Don Peterson, the out-going scientist-in-charge of the USGS’s David Johnston Cascade Volcano Observatory in Vancouver. “There aren’t any black-and-white answers.

“Scientists have learned to cope with varying degrees of uncertainties.”

Since September 1984, the seismic monitors ringing the mountain and installed on the lava dome in the volcano’s shattered crater have recorded no major earthquakes. Other instruments show little or no swelling in the crater or on the dome, which stands like a craggy lump of rocks 800 feet high and almost a half-mile in diameter.

The violent-but-brief steam bursts off the dome which periodically sent scientists scurrying for cover have been absent. The rate of the volcano’s lava production has been gradually decreasing since 1982.

“One interpretation is that it is storing up pressure,” perhaps for another eruption, said Peterson. “The other is that it may gradually be turning off.”

Sensitive measurements taken by a small plane flying over the volcano show Mount St. Helens is still venting as much as 75 tons of sulfur dioxide a day.

“It could be going into a prolonged silence or it could be building toward an eruption with an explosive component,” said Steve Brantley, another USGS scientist.

Scientists say there is evidence a typical eruptive cycle at Mount St. Helens can last 50 years, but those 50 years can be laced with 5-to-10-year stretches of inactivity.

Scientist do not expect a blast like the 24-megaton one on May 18, 1980, which blew 1,300 feet off the top of the once-snow-capped peak, left 57 people dead or missing, devastated 150 square miles of forest and blew an ash cloud around the world.

Recommended for you