Sunday, September 19, 2010 Period of rain and fog all day; 45 on the mountain, otherwise 62
We drove to the Johnston Observatory to see Mt.St. Helen and to learn about the May 18, 1980 eruption. But she was being very flirtatious today. One moment she would lift her veil of fog almost to crater height, and then she'd lower it again. We never did see the summit, but we learned a lot about the eruption from films, three ranger talks, murals, an electric map, and other displays.
Geologists had been studying Mt.St. Helen since March of 1980 when frequent earthquakes became stronger. They only had a Japanese volcano to compare to this mountain, so they were expecting a smaller, less explosive event. But on May 18th the dome that had been bulging by five feet a day finally blew, following a 5.1 magnitude earthquake. Thirteen hundred feet of the mountain's top launched outward and crumbled down the hillside in the largest landslide in recorded history. The Toutle Valley below was instantly scoured by heat, wind, ash, and rock. Winds reached speeds of 300 mph, the landslide reached a speed of 155 mph, and temperatures reached 660 degrees Fahrenheit.
The landscape within twenty miles of the volcano was drastically altered. The landslide splashed all of the water out of Spirit Lake, filled its bed with debris, and when the water flowed back, the lake was 600 feet higher and its surface twice as large as before. Meanwhile lahar (a mudflow composed of pyroclastic material, rocky debris, and melted glacial water) rushed down Toutle Valley wending its way around hummocks (mounds of dense volcanic rock) and rerouted the flow of the river. Nearby Coldwater and Castle Creeks became lakes. Trees closer to the blast were flattened like giant toothpicks, and the fiery winds burned the branches and leaves off those farther away, leaving a ghostly forest of barren, dead trees.
The human side of the story is also documented at the Observatory. Four loggers were working when the blast occurred. Two tried to find their way out and died. Two were rescued, but one later died of his burns. One couple, camping downriver, was swept away. The husband pulled his wife out of the lahar by her hair, and together they clung to floating logs until they were rescued. A young family was also camping near the river. When a helicopter was sent to rescue them, those aboard insisted the mother drop her "backpack" before being drawn up. What they did not know was that the "backpack" was actually her four-month-old baby. When she refused, she was boarded anyway. Imagine the surprise of that crew.
David A. Johnston, a thirty-one-year-old geologist, was monitoring the volcano from a ridge five miles away that fateful morning. He sensed that it was about to blow, yet he remained on duty. His last words were the warning, "Vancouver, Vancouver, this is it!" He was never found, and the observatory is named in his honor.
But a lot has changed in thirty years. Silver firs, which were bent in half under the weight of the ash, straighened themselves and fathered new saplings. Alpine lupines, making their own food from the soil, soon began to reappear. Pocket gophers survived, sheltered in their burrows. Their digging around the entrances to their homes loosened the soil, preparing it to receive new, wind-blown seeds. Elk migrated around the mountain, their dung also introducing more seeds to this barren region. Although evidence of this catastrophic day is everywhere, nature is busily healing and restoring her land.
Maybe what we have learned from our visits to all of these national parks is that we live in an amazing, varied country with natural resources of unimaginable beauty capable of rebounding from the sometimes destructive intrusion of man.
TODAY'S ROUTE: from Elma, US 12S to I 5S to exit 63; then WA 505 to WA 504 to its end in MT.St. Helen's National Monument; retrace WA 504 to I 5S at exit 49 to Longview, WA