August 9, 2012 | 5
Dawn arrives early in the Pacific Northwest spring. The clouds are usually thick enough to filter the light to the satisfaction of all but the lightest sleepers, but on the morning of May 18th, 1980, 5:30am saw the sun rising in cloudless skies. It called all rain-locked residents to seize a sunny spring day while the opportunity lasted. Sunlight shone on the ash-dusted flanks of Mount St. Helens, and cast shadows in the fractures in the bulge. The mountain, so recently wracked with steam explosions and rocked by earthquakes, had regained some serenity.
Something woke Dr. David Johnston of the USGS early that morning. It might have been birds, who tend to get rather vocal when the sun shines here. It might have been the Oregon Army National Guard’s overflight to check thermal anomalies before solar heat could compete with volcanic sources. There may have been something else that morning that urged him from his camper and back to his instruments as the sun crested the ridges. He checked the bulge three times in the next hour and a half, using geodetic equipment to assess its growth. It seemed to have slowed again: since yesterday, the rate was only about half a meter (2 feet) per day. Still screaming fast for a geologic process, to be sure, but considerably below what it had been.
He radioed in the last measurement at 6:53am Pacific Daylight Time.
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On a ridge 3 kilometers (2 miles) behind Dave, ham radio operator Gerry Martin would soon begin his own day. A member of the Amateur Radio Emergency Services and the Radio Amateurs Emergency Services, he was monitoring Mount St. Helens for the Washington Department of Emergency Services. He’d have a clear view of the mountain today.
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In Yakima, rock hounds and geologists had arrived for the Yakima Gem and Mineral Show. Washington Department of Natural Resources geologist Keith Stoffel was there to represent the Division of Geology and Earth Resources for WADNR. He and his wife, Century West Engineering Corp. geologist Dorothy Stoffel, knew they’d have a few hours to kill before the show. They chartered a plane for a flight out to Mount St. Helens. Neither of them had seen it since it roared awake.
They arrived with their pilot, Bruce Judson of Executive Aircraft, at 7:50am, and began their first pass over the volcano, eagerly observing. St. Helens vented a few wisps of steam from the bottom and southeast lip of her crater. The north face looked wet: large areas around Goat Rocks and Sugar Bowl glistened. They could see reddish-brown streaks left by debris flows, and wondered if those were hours or days old. Wet seeps wept on the south-facing wall of the crater. “Immense fractures” broke the south lip.
On the third pass, Judson thought those fractures had increased.
For their fourth pass, they swept wide to the northwest, taking in the whole of the mountain before approaching the summit from the west. They’d fly over on their way back to Yakima.
It was 8:32am.
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Fifteen kilometers (9 miles) east of the summit, University of British Columbia geology student Catherine Hickson and her husband Paul sat in the front seat of their car, eating breakfast. They’d driven down the day before and camped outside the predicted danger zone, hoping to see a little geology in action from a safe distance. Catherine was studying sedimentology, but an active volcano practically in the back yard is a sight few geologists can resist. They’d been treated to a quiet mountain and lovely weather. They’d risen in time to watch dawn flood the mountain slopes, and catch the few wisps of steam streaming from her summit in the cool of the morning. So far, the most excitement they’d experienced involved their dogs: both acted strangely that morning, subdued and anxious. They checked the animals over for illness or injuries: finding none, turned their attention to breakfast, barely paying attention to the currently quiet volcano outside their windshield.
At 8:32am, Paul glanced up, and yelled. Something was happening on the mountain.
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We expect volcanoes to give warning before they come undone. But they are geological phenomena: sometimes, the only warning we get before something catastrophic happens is the general seismic and phreatic precursor activity, which sometimes fades away with only a murmur. Sometimes, the warning given is followed too closely by catastrophe for us to react.
Several witnesses felt the magnitude 5.1 earthquake that morning. Some didn’t. It’s not certain whether Dave Johnston, alone at Coldwater II, felt anything at all. But we know he was among the first to see the enormous bulge on the north slope fail. He was staring it in the face. And when it came down, he knew. Grabbing his radio, he shouted, voice cracking with the intensity of the experience, “Vancouver! Vancouver! This is it!”
Vancouver never heard. Something, possibly the eruption itself, interfered: his last transmission was picked up by a ham radio operator who recorded those words, together with others too garbled to understand, on the tape recorder hooked to his unit. He relayed the message, and tried to reestablish contact. But Dr. David Johnston and Coldwater II were gone.
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On the ridge behind Dave, Gerry Martin had radioed the Washington Department of Emergency Services when the eruption started, providing a cool and concise description of the catastrophic failure of the north slope, the resulting avalanche, and the blast cloud that emerged as the confined cryptodome was suddenly released. He had an extra moment before the blast and debris avalanche reached him, saw them overrun Dave Johnston and Coldwater II. “The camper and the car just over to the south of me are covered,” he told the DES respondent. “It’s going to get me, too.”
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Flying toward the summit, Keith and Dorothy Stoffel noticed rock and ice sliding down the walls of the summit crater. Judson banked his aircraft for a better view. In a WA DNR paper summarizing the eruption (pdf), Keith described what he saw:
Within a matter of seconds, perhaps 15 seconds, the whole north side of the summit crater began to move instantaneously. As we were looking directly down on the summit crater, everything north of a line drawn east-west across the northern side of the summit crater began to move as one gigantic mass. The nature of movement was eerie, like nothing we had ever seen before. The entire mass began to ripple and churn up, without moving laterally. Then the entire north side of the summit began sliding to the north along a deep-seated slide plane. I was amazed and excited with the realization that we were watching this landslide of unbelievable proportions slide down the north side of the mountain toward Spirit Lake. We took pictures of this slide sequence occurring, but before we could snap off more than a few pictures, a huge explosion blasted out of the detachment plane. We neither felt nor heard a thing, even though we were just east of the summit at this time. Dorothy saw the southern portion of the summit crater begin to crumble and slide to the north just after the initial explosion.
From our viewpoint, the initial cloud appeared to mushroom laterally to the north and plunge down. Within seconds, the cloud had mushroomed enough to obscure our view. At about this time, the realization of the enormous size of the eruption hit us, and we focused our attention on getting out of there.
In the midst of the eruption, Judson dove for speed. Even at 200 knots, the blast cloud nearly overtook them. He turned them south, away from the north-directed blast and the east-blowing winds, and managed to outrace disaster. They landed safely in Portland, having witnessed the cataclysm from 0 kilometers away.
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Seventeen kilometers (10.5 miles) northeast of the summit, University of Washington geophysics student Keith Ronnholm, camping with photographer friend Gary Rosenquist and other companions in Bear Meadow, missed the start of the avalanche by ten seconds. When he emerged from his camper, “The bulge was moving… the whole north side was sliding down.” He watched the first eruption clouds form at the “cirque-like wall” left by the landslide block as the landslide disappeared from view behind a ridge. He and Gary photographed the developing eruption: the dark one that rose from the summit crater, and another, lighter, boiling out from the gaping wound in the north flank. He watched that second cloud expand nearly spherically, with one arm racing to the north after the avalanche. When the cloud hit the ridge closest to St. Helens, it bounded up in a seething, roiling mass.
They shot an extraordinary sequence of photographs before realizing they needed to flee.
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Catherine Hickson would write to a friend a week later, describing what she saw that day:
…The most incredible sight was occurring before our eyes - a large chunk of the mountain was avalanching down the slope perpendicular to our position, then a small cloud of black ash billowed up from below where the avalanche had occurred – the bulge on the side of the mountain had just broken away…. This was followed by a large puff of ash from farther up, then all hell broke loose as an enormous column of billowing black ash extended from the upper puff all the way down the mountainside to the second explosion, growing larger by the second enveloping it and in milliseconds extending far to the north….
An incredible black cloud was cascading down the mountainside, fed by the billowing columns soaring upwards into a huge mushroom cloud. “Nuée ardente” immediately came to mind as it became obvious nothing would stop it – not even the deep river valley that lay between us and the mountain. So we fled…
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Red lightning streaked from ash cloud to ground as Keith Ronnholm and his fellow campers drove to safety. About seven or eight minutes after the spectacular start of the eruption, rocks began pelting them from the ash cloud above their heads. It lasted less than a minute, and he was able to safely collect samples. Volcanic material began splattering the windshield, followed by heavy drops of mud that flattened into three-quarter inch discs as they hit. Mud stopped falling, replaced by ash, then mud again. This time, the ashfall became so thick he couldn’t see; it tapered off only gradually. He and his friends reached safety some time later, bearing photographs that would provide geologists with critical insight into the opening stages of the eruption.
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Bolts of lightning stabbed from cloud to ground as Catherine and Paul Hickson fled south on a logging road. The ash cloud loomed behind them, “roaring and crashing with an incredible fury.” The sun vanished; ash rained down, and then the road turned back north, taking them back toward all that fury, into a mud rain and a ground-hugging ash cloud. The mud rain forced them to retreat. They found other campers at a site they’d passed earlier, whose detailed maps showed several possible routes out of the cataclysm. They’d spend the next several hours tracing various routes, cut off by mud flows that destroyed bridges, while the mountain roared. Pumice fell, threatening to break the windshield of the car that had gone ahead to scout. Catherine collected some of it from a lighter fall, which would later be analyzed in the University of British Columbia labs.
They passed the Muddy River valley, where a lahar had swept through, leaving the trees not ripped away “covered in mud halfway up the trunks,” and replacing the river with thick, gray mud. Finally, at noon, they found a route through the destruction, sped over the Lewis River bridge, and gave a report to officers manning a roadblock further down. People had been trying to drive up for a closer look at the volcano. They looked at the Hicksons’s ash and mud spattered car, listened to them describe their escape, and seemed to change their minds about a closer view. The Hicksons crossed the Columbia into Oregon, and made it home to Vancouver, BC just before I5 was shut down due to ash fall and the threat to bridges from lahars.
They’d been right on the fringe of the blast zone. They’d survived.
After Mount St. Helens nearly killed her, Catherine Hickson would never be the same. She gave up sedimentology. Thirty years later, she would explain to Seattle Met magazine what that day had done:
“I was frightened that entire morning,” she recently recalled. “But it changed me. It changed what I studied. It changed what I became.” She became Canada’s most celebrated volcanologist.
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Geology student Harry Glicken, who had been scheduled to be on the mountain that morning, spent a frantic afternoon talking his way on to any search and rescue helicopter that would take him, trying to find Coldwater II, trying to find Dave. But they were gone. The top of the mountain was gone. Everything was gone.
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Those geologists who witnessed the catastrophic eruption of May 18th, 1980, along with others caught in the fury of the unleashed cryptodome, would be essential to piecing together the events of that morning. In the immediate aftermath, things were too chaotic, the volcano too dangerous, to understand exactly what had happened. The entire landscape had changed in moments: landmarks, forests, people: all missing, all destroyed.
USGS geologists later interviewed survivors, and with their statements and photographs, observations from scientists and searchers flying through the chaos, and other bits and fragments of evidence collected from instruments that had survived, were able to piece together the events of that day. The magnitude 5.1 earthquake had come first. It probably shook that perilously unstable bulge loose, fulfilling David Johnston’s prediction that it couldn’t stabilize without coming down. It cascaded down in multiple slump blocks, one of which uncovered the cryptodome. Released from confining pressure, gasses within the thick dacite magma came out of solution and blew through upper slump block as it fell. The horizontal eruption grew far faster than one that shot vertically from the summit, and subjected people within its reach to brief but blazing heat, burning anyone not protected by vehicles or fallen trees. No one close to the mountain heard a concussive blast, just roaring and rumbling. What struck the interviewers the most was that few seemed to hear entire forests of mature trees being blown down.
The blast cloud roaring from the breached north flank seemed to hug the ground: climbers on Mounts Rainier and Adams watched it dip into valleys, vanishing from sight until it reappeared over ridgetops. The direct blast, that long arm Keith Ronnholm had seen emerging from the sphere, traveled at 140-150 meters per second (313-335 miles per hour)), although it didn’t sustain those speeds for long.
When the eruption finished, 600 square kilometers (230 mi2) lay devastated. Lahars and ash fall impacted many hundreds more, ripping out bridges, destroying roads and streams, and shutting out the sun.
The cataclysm had come.
Previous: Interlude: Moment of Silence.
Cheng, Cliff: In Honor of Jerry Martin, W6TQF, and Reid Blackburn, KA7AMF. Last accessed 8/9/12.
Foxworthy, Bruce L. and Hill, Mary (1982): Volcanic eruptions of 1980 at Mount St. Helens: the first 100 days. U.S. Geological Survey Professional Paper 1249.
Hickson, Catherine J. (2005): Mt. St. Helens: Surviving the Stone Wind. Vancouver, BC, Canada: Tricouni Press.
Korsec, M.A., Rigby, J.G., and Stoffel, K.L. (1980): The 1980 Eruption of Mount St. Helens, Washington. Department of Natural Resources Information Circular 71. (PDF)
Lipman, Peter W., and Mullineaux, Donal R., Editors (1981): The 1980 Eruptions of Mount St. Helens, Washington. U.S. Geological Survey Professional Paper 1250.
Thompson, Dick (2000): Volcano Cowboys: The Rocky Evolution of a Dangerous Science. New York, NY: Thomas Dunne Books.
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