Mt. St. Helens National Volcanic Monument

Mt. St. Helens, in the state of Washington, is best known for the enormous volcanic eruption that took place on May 18, 1980. Although seismic activity gave scientists ample warning that an eruption was coming and many people were evacuated from the region well in time, the 1980 eruption remains the deadliest and most economically costly volcanic eruption in the history of the United States. Fifty-seven people were killed. Some 250 homes, 47 bridges, and many miles of highway and railroad lines were destroyed.

The eruption, which blew away the north face of the mountain, caused a massive avalanche of debris, including rock, ash, pumice and the trees that once populated the mountain. Much of the debris – including trees still visible today as bleached logs – fell into nearby Spirit Lake. The eruption reduced Mt. St. Helens itself from its previous elevation of 9,677 ft (2,950 m) to its present 8,365 ft (2,550 m). The once-conical summit of the mountain was replaced by horseshoe-shaped crater (or caldera) that is one mile (1.5 km) wide. The energy released by the eruption had 27,000 times the destructive force of the atomic bomb dropped on Hiroshima. Ash fallout from the eruption reached as far as Oklahoma and New Mexico.

Pyroclastic flows (fast-moving waves of hot gases, rock and ash) flattened trees and buildings over a 230 square mile area. Many trees fell in patterns reflecting the direction of the flows and still lay today where they fell more than a quarter century ago. Other trees were left standing but killed by the heat and remain today as eerie skeletons of a once lush pine forest.

Mt. St. Helens – named for the British diplomat Lord St Helens, a friend of explorer George Vancouver who surveyed the area in the late 1700s – remains active today. It periodically vents off steam and ash and a new dome of lava is building within the crater left by the 1980 eruption. It is only a matter of time before the volcano erupts once again.

Although Mt. St. Helens – located 96 miles (154 km) south of Seattle, Washington and 53 miles (85 km) northeast of Portland, Oregon – is the most active volcano in the Cascade mountain range, it is by no means the only one. Others include Mt. Adams and Mt. Ranier in Washington and Mt. Hood in Oregon.

Visiting Mt. St. Helens National Volcanic Monument is a bit of a challenge. There are two locations that offer good views of the north face of the mountain – the region that shows the most destruction from the 1980 eruption. One is Windy Ridge and the other is the Johnston Ridge Observatory (named after David A. Johnston, a 30-year-old volcanologist with the United States Geological Survey who was killed during the eruption while manning an observation post some six miles from the volcano). Unfortunately, while Windy Ridge and Johnston Ridge are rather close as the crow flies, they are more than a three-hour drive apart by road. My time did not permit a visit to Johnston Ridge, but there are several photos in the slide show above from Windy Ridge. Also, while driving to Windy Ridge, it is possible to stop off at one of the overlook points and hike the mile or so down to Spirit Lake.

By the way, if you want to keep tabs yourself on the latest activity at the volcano, check out the Mount St. Helens VolcanoCams operated by the U.S. Forest Service.