Mount ST. Helens National Volcanic Monument

Shortly after leaving Yakima we were able to take the above picture of Mount Rainier. After leaving the highway we had to go on twisting back county roads for more than 65 miles in total. Shortly before arriving at the Windy Ridge Lookout we stopped at a scenic view point overlooking Spirit Lake.

On the left shore of the lake you see floating wood from the trees which were taken down during the last eruption. Mount St. Helens and its surroundings now serve as a giant lab to see how habitats recover after massive events. 

The sequence of events and its magnitude are outlined in this document created by the US Forest Services:

On March 20, 1980, a series of small earthquakes signaled the awakening of Mount St. Helens from a 123-year slumber.

Over the next two months more than 10,000 earthquakes followed as magma moved into the volcano, wedging the volcano apart at a rate of five feet per day. The rising forest in less than five minutes. Heat from a rising plume of volcanic ash melted glacial ice creating cement-like slurries of rock and ash called mud flows. Superheated avalanches of hot gas, magma caused a visible swelling of the volcano’s north flank creating a feature that scientists called ‘the bulge’.

Many geologists weren’t surprised by Mount St. Helens’ awakening. Two years earlier geologists had predicted Mount St. Helens would erupt “…and may even do so before the end of the century.” ash, and pumice called pyroclastic flows flowed into the valley north of the crater. The resulting landscape was a seemingly gray wasteland. Careful study revealed evidence of a young, upstart volcano that had staged more than a dozen major eruptions in the past 4,000 years.

On May 18, 1980, a magnitude 5.1 earthquake triggered the collapse of the volcano’s bulging north flank and summit in a landslide of historic proportions. Magma trapped within the volcano, suddenly relieved of pressure, exploded outward in a lateral blast that blew down 230 square miles of forest in less than five minutes. Heat from a rising plume of volcanic ash melted glacial ice creating cement-like slurries of rock and ash called mud flows. Superheated avalanches of hot gas, ash, and pumice called pyroclastic flows flowed into the valley north of the crater. The resulting landscape was a seemingly gray wasteland. 

We enjoyed a very informative talk given by a park ranger and then climbed the viewpoint, from which you can look into the remaining parts of the Mountain. 

Besides Windy Ridge there is one additional site we wanted to see, which is the Johnstone Observatory, named after one of the scientists killed during the May 1980 eruption. From there you have an excellent view into the mountain and the mudland. Also you can observe the lateral blast’s full impact as you transition from green forest to standing dead forest to blown down forest. In many areas tress which fell down are actually aligned indicating the direction of the blast in that particular area.