. The blackened top of Mount St. Helens, seen here on March 30, 1980, stands in contrast to the white clouds and Oregon's Mount Hood in the background. To the right is light smoke from Mount St. Helens. A day earlier the volcano spit out heavy smoke, ash and shards of ice 5 feet long.
. Vulcanologist David Johnston works at his camp near what is now known as Johnston Ridge on May 17, 1980. At 8:32 a.m. the next morning, Johnston radioed the famous "Vancouver, Vancouver, this is it!" transmission to the U.S. Geological Survey office in Vancouver, Wash. He was among 57 people who perished in the massive eruption that followed.
. Mount St. Helens erupts on May 18, 1980, sending a plume of ash, smoke and debris skyward. The landslide that followed covered 23 square miles, buried the Toutle River's north fork under 150 feet of debris and moved at speeds up to 150 mph. The eruption reached about 80,000 feet in less than 15 minutes.
. The ash plume rises from Mount St. Helens on May 18, 1980. The plume moved eastward at an average speed of 60 mph, with ash reaching Idaho by noon.
. Clouds of ash from Mount St. Helens are shown over the airport in Ephrata, Wash., a day after the blast. Ephrata is about 100 miles northeast of the volcano as the crow flies. Clouds of ash reached as far away as western Montana. Traces of ash were blown across the United States in three days, and circled the Earth in 15 days.
. Noticing a sudden rush of water from the Toutle River below Mount St. Helens, these four young men, one of whom is pulling himself onto the railcar, run for higher ground. They made it to safety, but the horses they had been trying to save did not.
. The streets of Yakima, Wash., were dark at 3:00 PM after an eruption at Mount St. Helens, May 18, 1980. White volcanic ash covers the streets and passersby had to wear masks to avoid breathing the ash.
. The lateral blast from Mount St. Helens moved at 300 mph or more, and literally blew down thousands of trees, some of which are shown here along with a singed area at left. More than 4 billion board feet of usable timber, enough to build 300,000 two-bedroom homes, was damaged or destroyed in the blast.
. Two people died inside this camper truck about eight miles from Mount St. Helens. Downed trees and piles of ash surround the vehicle in this photo, taken on May 26, 1980. The markings in the ash in front of and behind the camper were left by searchers who found the victims.
. Days after the eruption, people were still shoveling ash off sidewalks, rooftops, roads and cars. This resident of Ritzville, Wash., takes a break from shoveling on May 19, 1980.
. Someone in Yakima, Wash., tried to find humor in the situation, taking a sign for St. Helens Street and placing it in some ash to reflect this road's condition after Mount St. Helens erupted. Yakima is about 50 miles east of the volcano as the crow flies.