DESCRIPTION:
Windy Ridge Vicinity

A stunning viewpoint overlooking a vast pumice plain, Windy Ridge Viewpoint takes you to within 4 miles of an active volcano. Listen to an interpretive talk or venture up 361 steps to a viewpoint of the volcano and Spirit Lake. The Northwest Interpretive Association provides a mobile sales outlet here.

NOTE: Viewpoint services are limited to vehicle parking, interpretive signs, composting toilets, and an uncovered outdoor amphitheatre featuring live interpretive talks. There are no phones or running water at this site.

The road to Windy Ridge is usually plowed by the end of May an remains open through October. The road is closed by winter snowfall from November through May.

[Graphic,12K,InlineGIF]
View westward from Windy Ridge Overlook, down valley of the North Fork Toutle River, with Spirit Lake in the foreground and Mount St. Helens to the left.
Modified from: Doukas, 1990, Road Guide to Volcanic Deposits of Mount St. Helens and Vicinity, Washington: U.S.Geological Survey Bulletin 1859

Windy Ridge parking lot is at end of the public road, about 4 miles (6.5 kilometes) from the summit. The blast deposit here is about 3 feet (1 meter) thick, veneered by 1980 air-fall deposits. The best viewpoint is reached by a short climb to the top of the hill just north of the parking lot. All of Spirit Lake, including the floating logs, the swash zone from the water wave generated by the avalanche, and much of the crater, is visible. The debris-avalanche deposit dams Spirit Lake and forms the hummocky topography in the distance. On the south end of Harrys Ridge, (the first ridge west of Spirit Lake) all trees and soil were removed down to bedrock by the avalanche and blast. Light-gray pyroclastic-flow and ash-cloud deposits, mainly from May 18 but also from June 12 and July 22, 1980, cover and lap against the debris avalanche south of Spirit Lake. Many of these deposits have been stripped or buried by lahars generated by rapid snowmelt during explosions in the lava dome. Several fumaroles apparently rooted in the pyroclastic flows still steam in 1986, visible best on humid days. Much of the northern part of the crater is visible from here, but in October 1986 only the very top of the dome, 918 feet (280 meters) high, 2,600 feet (800 meters) wide, and located in the southern part of the crater, shows overt the shoulder of Sugar Bowl dome. The water level in Spirit Lake is maintained by a gravity-fed tunnel cut through Harrys Ridge to South Coldwater Creek, which drains into the North Fork Toutle River. The portal is visible about halfway along the west shore of the lake. The spillway prevents overtopping and possible catastrophic erosion of the unstable debris-avalanche blockage. Between November 1982 and April 1985, U.S. Army Corps of Engineers contractors maintained lake level by using barge-mounted pumps that withdrew water and sent it down a channel on the pumice plain. ... The altitude of the lake before the eruption was 3,198 feet (975 meters); in fall 1980, it was 3,408 feet (1,039 meters), and the level controlled by pumping was 3,463 feet (1,056 meters), a total increase since May 17, 1980, of 265 feet (80 meters). Current lake level is 3,438 feet (1,048 meters). A tiny shed high on Harrys Ridge houses surveying and radio equipment used by USGS volcanologists to monitor volcanic activity; most current monitoring is conducted within the crater and on the dome. The USGS notifies the USFS and other Government agencies when monitoring indicates significant changes in activity. All decisions regarding access and land use in Mount St. Helens National Monument are made by the USFS.

Windy Ridge Viewpoint. Restrooms. Ascend steps for best views of Spirit Lake. Harry's Ridge, hummocky debris avalanche that dams Spirit Lake, the Pumice plain, and lahar fan directly north of crater. The Pumice Plain was at one time entirely covered by 1980 pyroclastic flows, but lahars generated by eruption-induced snow melt in the crater have swept away or covered most of the flows due north of the crater. part of the Pumice Plain west of the lahar fan still has an intact, though deeply gullied, primary surface.

The debris avalanche dammed and partly filled Spirit Lake, displacing water so that the surface of the new lake was about 61.5 m higher than before (1036.3 meters vs. 974.8 meters). Harry Truman, who stubbornly refused to vacate his lodge on the shore of Spirit Lake, was buried beneath about 45 meters of debris and 25 meters of water in the southwest corner of the lake. The avalanche formed an unstable debris dam that threatened to fail catastrophically when lake level rose to the approximate height of the low point on the dam. The Army Corps of Engineers began pumping the lake in November 1982 to stabilize water level at an acceptable elevation (1055.2 meters). This costly venture was ended in April 1985 when a 2.6-kilometer, 14-million-dollar, tunnel was opened through Harry's Ridge and began to serve as a gravity-fed controlled outlet for the lake. The tunnel is 3.4 meters in diameter, has a grade of 1 percent, and was constructed with a tunnel-boring machine advancing at an average rate of 20 meters per day for 5.5 months. The portal to the tunnel, which crosses the St. Helens seismic zone with a capability of a M=7 earthquake, is visible about halfway along the western shore in basaltic andesite and breccia. Opening the tunnel caused lake level to drop about 6.7 meters to the elevation of the portal, resulting in the prominent shoreline with stranded logs. Water from the tunnel eventually enters the Toutle River after flowing through South Coldwater Creek and Coldwater Lake.

The northwest corner of the 1980-86 dacite dome can be seen from the hilltop. At the time of writing (December 1988) the dome had last grown in October 1986 and was about 267 meters high, 1,060 meters long, 860 meters wide, and had a volume of 74.1 x 10^6 cubic meters. Its volumetric rate of growth and geometry were notably regular, and each period of growth was easily predicted on the basis of precursory ground deformation and seismicity.

Windy Ridge Viewpoint: Windy Ridge is one of the best places to get an overview of the area devastated by the 1980 eruption. The landscape is littered with sand and gray rocks from that event. Deposits of the debris avalanche are visible to the west. These include the lower parts of The Spillover, where the debris avalanche traveled up over Johnston Ridge and into the South Coldwater area.

The blast stripped most of the vegetation and some soil from many of the older bedrock surfaces, revealing to geologists and visitors previously hidden chapters in the geologic history of the area.

Rockfalls from the crater walls stir up ash clouds that curl over the edges of the crater rim, especially in late summer. A faint bluish-white volcanic gas plume is often visible rising from the Lava Dome, and sometimes fumaroles or clusters of fumaroles can be seen there.

A walk up the steps on the hill north of the parking lot provides a better view of the devastated area adjacent to Spirit Lake. The 1980 debris avalanche roared over part of a ridge that protrudes into Spirit Lake from the north and carried all the downed trees off the slope and into the lake, leaving a distinct trimline. The avalanche also displaced water from Spirit Lake, creating a giant wave that carved a slosh line along the shore. Many of the logs that now float in the lake were carried in by this wave; others have been eroded off the slopes since than. Wind moves the logs to different locations on the lake.

The water level of Spirit Lake is maintained at about 3,406 feet (1,038 meters) by draining water through a gravity-feed tunnel completed in 1985. The 2,500-feet (762 meters) -long tunnel was cut through Harrys Ridge (named form Harry Truman, the Spirit Lake resident who refused to leave his home and was killed by the May 18, 1980, eruption) to South Coldwater Creek. The portal is just visible about midway along the western shore of the lake. Had the lake level not been stabilized, its dam probably would have been breached, possibly causing catastrophic floods in the Toutle River.

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