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.
Suiattle Glacier Suiattle Glacier is located in the Glacier Peak Wilderness in the U.S. state of Washington. The glacier is within Mount Baker-Snoqualmie National Forest and nearly touches Honeycomb and White River glaciers separated from them by an arête off the Kololo Peaks at its uppermost reaches. Suiattle Glacier has retreated significantly since the end of the Little Ice Age, and from approximately the years 1850 to 1924 lost 1400 m of its length. Between 1924 and 1940, the glacier retreated an additional 900 m , then during a cooler and wetter period between 1967 and 1979, the glacier had a small advance of 20 m . Between 1979 and 2005 the glacier again retreated 178 m upslope.