On what date did the 1980 eruption of Mount St. Helens, in which "Crater Glacier" was formed, occur?
1980 eruption of Mount St. Helens On May 18, 1980, a major volcanic eruption occurred at Mount St. Helens, a volcano located in Skamania County, in the state of Washington, United States. The eruption (a VEI 5 event) was the only significant volcanic eruption to occur in the contiguous 48 U.S. states since the 1915 eruption of Lassen Peak in California. However, it has often been declared as the most disastrous volcanic eruption in United States history. The eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain's north slope.
Sawtooth Mountain Sawtooth Mountain is a shield volcano, and part of the polygenetic Indian Heaven Volcanic Field in Washington, United States. It is located midway between Mount St. Helens and Mount Adams, and dates from the Pleistocene and Holocene. Sawtooth Mountain is the third highest point at 5354 ft . The mountain forms a series of welded volcanic rock spires, an eroded remnant of an ancient shield volcano. Sawtooth Mountain is the third highest point in the Indian Heaven Wilderness Area. While Sawtooth Mountain is not the highest, its craggy appearance makes it one of the most namesake peaks in the Indian Heaven Volcanic Field.