A major disaster happened 31 years ago. On May 18, 1980, at 8:32
a.m. Pacific Daylight Time, a magnitude 5.1 earthquake shook
Mount St. Helens. The bulge and surrounding area slid away in a
gigantic rockslide and debris avalanche, releasing pressure, and
triggering a maassive pumice and ash eruption of the volcano.
1,300 feet (400 meters) of the peak collapsed or blew outwards.
As a result, 24 square miles (62 square kilometers) of valley
was filled by a debris avalanche, 250 square miles (650 square
kilometers) of recreation, timber, and private lands were
damaged by a lateral blast, and an estimated 200 million cubic
yards (150 million cubic meters) of material was deposited
directly by lahars (volcanic mudflows) into the river channels.
61 people were killed or are still missing. The Mount St. Helens
volcano is located in the Cascade Range. It’s a part of the
Cascade Volcanic Arc, a segment of the Pacific Ring of Fire that
includes over 160 active volcanoes. This volcano is well known
for its ash explosion