Sunday, August 24, 2008

At Long Last, Driving Out to the Volcano

On May 18th, 1980, after weeks of Pilinian-style ash eruptions and ominous swelling, Mt. Saint Helens detonated. Corresponding with a 5.1 earthquake, the largest avalanche in historical times exposed the volcano's central chamber, unleashing a blast that propelled the mountain's northern mid-section and northern glaciers north towards Johnston Ridge at the speed of sound. Over a nine-hour period the volcano unleashed the equivalent explosive force of 27,000 Hiroshima bombs and sent a miles-wide column of ash into the stratosphere.

I have wanted to see this mountain ever since I was a boy.

Looking into the devastated area. Mt. Adams is visible on the far left.

Driving in the blast zone, 28 years after.

A side view of the avalanche and the initial blast that it unleashed.

An odd aspect of the explosion is that its noise was carried upward into the stratosphere, creating a sixty-mile cone of silence around the event. A survivor, standing 14 miles away claimed that he could hear the roar of thousands of trees being ripped out of the ground, but he heard nothing of the blast itself.

This was a heavily forested mountainside clad in several meters of soil until it was scoured clean on the fateful morning.

Johnston Ridge. You can see where the avalanche flowed up and over this 1,500ft ridge.

The scrap marks are from the avalanche's impact, which blew away several feet of soil and carved into the base rock itself.

Mt. Adams (12,276ft) and the remains of Spirit Lake. The white plain is actually hundreds of thousands of bleached logs.

A USGS photo of the mountain as seen from Johnston Ridge a day before the blast

As it looks today to my camera

Visible within the crater are two domes, the growth of which have helped to slowly rebuild the mountain. These active, steaming structures are now surrounded by the Shoestring glacier

A morphing map of the second dome’s 2004-2007 growth within the crater. This new Whaleback dome is located behind the first dome left over from the 1980-1986 eruptive phase. The lobes moving down the crater’s sides are the Shoestring glaciers.

The Johnston Ridge Observatory webcam captures a days worth of steaming and lava flows during October, 2004.

Pressured from below, the second dome undergoes a partial collapses as a team of USGS geologists looks on.

The volcano as seen from the Johnston Ridge Observatory

The observatory itself; the home my favorite web cam

Leaving the blast area

Some USGS photos of the mountain, some of which also show Mt. Rainier

Mt.Rainier above Tacoma. Hopefully I can make it up to Paradise Lodge on the south side before the cloudy season cloaks the mountain in unpredictable mists.

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