Mount St. Helens

USA / Washington / Morton /
 volcano, stratovolcano
Mount St. Helens is an active stratovolcano in Skamania County, Washington, in the Pacific Northwest region of the United States. It is located 96 miles (154 km) south of the city of Seattle and 53 miles (85 km) northeast of Portland, Oregon. The mountain is part of the Cascade Volcanoes and the Cascade Range which takes its English name from the British diplomat Lord St Helens, who was a friend of George Vancouver, an explorer who made a survey of the area in the late 18th century. Mount St. Helens is a part of the Pacific Ring of Fire that includes over 160 active volcanoes. This volcano is well known for its ash explosions and pyroclastic flows.

Mount St. Helens is most famous for its catastrophic eruption on May 18, 1980. The 1980 eruption of Mount St. Helens was the deadliest and most economically destructive volcanic event in the history of the United States. (In 1912, Mount Katmai, Alaska, was the site of the largest volcanic eruption in U.S. history.) Fifty-seven people were killed; and 250 homes, 47 bridges, 15 miles (24 km) of railways and 185 miles (300 km) of highway were destroyed. The eruption caused a massive debris avalanche, reducing the elevation of the mountain's summit from 9,677 feet (2,950 m) to 8,364 feet (2,550 m), and replacing it with a mile-wide (1.5 km-wide) horseshoe-shaped crater. The debris avalanche was up to 0.7 cubic miles (2.3 km³) in volume, making it the largest in recorded history. However, the scale of the blast is considered minor when compared with past debris avalanches elsewhere on Earth.

As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted. The largest of the dacite domes formed the previous summit; and off of its northern flank sat the smaller Goat Rocks dome. Both were destroyed in the 1980 eruption.

peakbagger.com/peak.aspx?pid=2353

www.summitpost.org/mount-saint-helens/150360

www.wilderlist.app/mountain/5f04d20d676f544db0f0c635
Wikipedia article: http://en.wikipedia.org/wiki/Mount_St._Helens
Nearby cities:
Coordinates:   46°11'55"N   122°11'17"W

Comments

  • That's because the blast of the May 18, 1980 eruption was directed to the north due to the volcano's summit sliding in that same direction.
  • Yep, and the part of the mountain that blew off the top is pretty much lying around in the valley between all the lakes on the map (Castle, Coldwater and Spirit). The eruption blew right into Johnston ridge and the flow of lava, sediments and other debris washed down the Toutle River valley. Even today they are dealing with debris from the volcano. Most of the trees that were destroyed have since been regrown, except in the immediate gray zone.
  • I was living in Cheyenne at the time and the dust covered everything. Migratory birds were landing in the parking lot at work. What a mess.