Images

Photo 10 of 15: Sinkhole chimney after pool collapse. View to south across the sinkholne. For a time after the pool collapse and introduction of the pool water into the sinkhole, there was a noticeable increase in slope movement, especially deeper in the sinkhole. The house and building parts broke up further and disappeared.

Photo 11 of 15: Intersection of South Denning Drive and West Comstock Ave. Sinkhole is edging close to Denning Drive. One block of Comstock Ave was swallowed. View to south on Denning Drive adjacent to the sinkhole.

Photo 12 of 15: Water level has risen and is now apparent in sinkhole since pool collapse and house swallowed. View to south across the sinkhole. The rising water level is likely a result of the debris plugging the conduit into the Floridan aquifer. Water level is rising to assume a position more consistent with that of the surficial aquifer. (3 p.m.)

Photo 13 of 15: Water level in sinkhole chimney continued to rise. View to east across the sinkhole. (6 p.m.)

Photo 14 of 15: Remnants of community pool in sinkhole. View to east across the sinkhole.

U.S. Army Corps of Engineers preformed dredging projects on the Toutle, Cowlitz, and Columbia Rivers and by 1987 enough material had been removed to build a 12 lane highway, one-foot thick from New York, NY to San Francisco, CA.

Small phreatic eruption of Mount St. Helens in the spring of 1980, before the May 18, 1980 blast.

The volume of the debris avalanche was nearly 2/3 cubic miles (2.5 cubic kilometers) of debris avalanche that slid from the volcano on May 18, 1980. That is enough material to cover Washington, D.C. to a depth of 14 feet (4 meters). The avalanche traveled approximately 15 miles (24 kilometers) downstream at a velocity exceeding 150 miles per hour (240 km/hr).

This October dome was taller than a nine-story building and wider than the length of three football fields. This dome was not the first dome to grow in the crater. In June and August 1980, two domes formed, only to be blasted away by the explosive events of July 22 and October 16.

Nearly 135 miles (220 kilometers) of river channels surrounding the volcano were affected by the lahars of May 18, 1980. A mudline left behind on trees shows depths reached by the mud.

Pumice blocks at the toe of a pyroclastic flow from the 1980 eruption sequence at Mount St. Helens.

Many smaller animals, such as gophers, mice, frogs, fish, and insects were hibernating below ground or under water on May 18, 1980, and they survived the blast. Larger animals such as bear (whose tracks are shown here), elk, deer, and coyotes have been moving back into the area as their food supplies increase.

This lake was once surrounded by lush forest and is within the area devastated by the directed blast, covered by ash and tephra, then inundated by pyroclastic flows. Remnants of the forest float on the surface of the lake. Mount Rainier (4,392 m or 14,410 ft) is in the distance. The view is from the south.

The direction of the blast, shown here from left to right, is apparent in the alignment of the downed trees. Over four billion board feet of usable timber, enough to build 150,000 homes, was damaged or destroyed.

For weeks volcanic ash covered the landscape around the volcano and for several hundred miles downwind to the east. Noticeable ash fell in eleven states. The total volume of ash (before its compaction by rainfall) was approximately 0.26 cubic mile (1.01 cubic kilometers), or, enough ash to cover a football field to a depth of 150 miles (240 kilometers).

Muddy River bridge crossing destruction from May 18, 1980 Mount St. Helens lahars.

After the May 18, 1980 eruption, Mount St. Helens' elevation was only 8,364 feet (2,550 meters) and the volcano had a one-mile-wide (1.5 kilometers) and approximately 600 m (2000 ft) deep horseshoe-shaped crater. View here is from the northwest.

Mount St. Helens soon after the May 18, 1980 eruption, as viewed from Johnston's Ridge.

Mount St. Helens soon after the May 18, 1980 eruption, as viewed from Johnston's Ridge.

Blowdown of trees from the shock-wave of the directed (lateral) blast from the May 18, 1980 eruption of Mount St. Helens. Elk Rock is the peak with a singed area on the left.

During the May 18, 1980 eruption, at least 17 separate pyroclastic flows descended the flanks of Mount St. Helens. Pyroclastic flows typically move at speeds of over 60 miles per hour (100 kilometers/hour) and reach temperatures of over 800 Degrees Fahrenheit (400 degrees Celsius).