From Wikipedia: "Mount St. Helens is most notorious for its catastrophic eruption on May 18, 1980 - 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 (298 km) 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 9,677 ft (2,950 m) to 8,365 ft (2,550 m), replacing it with a 1 mile (1.6 km) wide horseshoe-shaped crater. The debris avalanche was up to 0.7 cubic miles (2.9 km3) in volume."

Today I visited for the first time. Not far from the closest viewing area of the blast site, you can see Mount Hood and Mount Adams, with Mount Rainier visible a bit further away. The comparisons help a little bit in understanding the magnitude of the event.

I did not live in Yakima at the time of the eruption, but the friends who took me to the mountain today did live here. Yakima received nearly 3 inches of ash in the first 24 hours and was in darkness for 18 hours. The city removed over 544,000 metric tons of ash from the community.