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.
Herman LeRoy Fairchild Herman Le Roy Fairchild (April 29, 1850 – November 29, 1943) was an American educator and geologist. He was an early proponent of the theory of meteorite impact causing craters such as that of Meteor Crater, Arizona. Fairchild also left his mark on glacial geology. In that field he is best known for having accurately mapped the proglacial lakes of western New York. He did his field work between the 1888 and the early years of the 20th century. He located strand lines (beaches) and erosional surfaces, determined their altitude, and interpolated between them to show the extent of several large bodies of water. A series of lakes was created as the Wisconsinan glaciation ended and ice sheets retreated during the latest Pleistocene and early Holocene epochs. Fairchild discovered several outlets where each lake drained to the east or west.