Tree stump. Windy Ridge, Mt. St. Helens, Washington

Mount St. Helens is most famous for its catastrophic eruption on May 18, 1980, which was the deadliest and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; 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 8,365 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 (2.9 km³) in volume. The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied.

圣海仑斯火山位于美国西北的华盛顿州。 1980年5月18日，圣海仑斯火山猛烈爆发。喷发直接摧毁了250户住房，24公里铁路，300公里道路，47座桥梁。 有57人在火山爆发中丧生。喷出的火山灰堵塞了华盛顿州东北部的大部分道路，90号州际高速公路被厚厚的火山灰铺盖，使当地交通瘫痪一个星期。圣海仑斯火山的山体在爆发前是一个对称的圆锥体，被称为“美国的富士山”。在1980年的爆发中，山体北坡发生大规模滑坡，2.9立方公里的体积滑到山底，在山上留下一个巨大的扇形缺口。