answers: 2004
context: the volcanic activity, the termini of the glacier have still advanced, with a slight advance on the western lobe and a more considerable advance on the more shaded eastern lobe. Due to the advance, two lobes of the glacier joined together in late May 2008 and thus the glacier completely surrounds the lava domes. In addition, since 2004, new glaciers have formed on the crater wall above Crater Glacier feeding rock and ice onto its surface below; there are two rock glaciers to the north of the eastern lobe of Crater Glacier. Crater Glacier is the only known advancing glacier </s> 1980, eruption. In 1482, another large eruption rivaling the 1980 eruption in volume is known to have occurred. Ash and pumice piled northeast of the volcano to a thickness of ; away, the ash was deep. Large pyroclastic flows and mudflows subsequently rushed down St. Helens' west flanks and into the Kalama River drainage system. This 150-year period next saw the eruption of less silica-rich lava in the form of andesitic ash that formed at least eight alternating light- and dark-colored layers. Blocky andesite lava then flowed from St. Helens' summit crater down the volcano's southeast flank. Later, pyroclastic flows </s> 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 notorious for its major 1980 eruption, the deadliest and most economically destructive volcanic event in the history of the United States. Fifty-seven people were killed; 250 homes, 47 bridges, of railways, and of highway were destroyed. A massive debris avalanche triggered by an earthquake measuring 5.1 on the Richter scale caused an eruption that reduced the elevation of the mountain's summit from to , leaving a wide horseshoe-shaped crater. The debris
question: when was the last time mount saint helens erupted