Mount Thielsen, Oregon

Thielsen87_aerial_thielsen_09-87.jpg
Aerial view Mount Thielsen, Oregon.
USGS Photograph taken in September 1987, by W.E. Scott.
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Mount Thielsen Volcano

Mount Thielsen Volcano
-- Geographic Setting, Geologic and Eruptive History
Mount Thielsen is similar to many of the basaltic andesite shields that form the bulk of the High Cascades in Oregon. It consists of a central pyroclastic cone built of scoriaceous to pumiceous cindery tuff and coarse breccia. Variations in grain size define the bedding, which is made more spectacular by the alteration of glassy tephra to colorful palagonite. The beds mainly dip 10-40 degrees away from the central conduit-filling plug, although locally these beds have been steepened and even overturned during the plug's intrusion, a feature unreported from other shields in the Cascade Range. Dikes and sills lace the cone. -- Excerpt from: Sherrod, 1990, IN: Wood and Kienle, 1990

"Climb A Volcano"

The trail is a steep climb, particularly above timberline beyond which there are no markers. The last 200 feet is a difficult hand-over-hand climb.

The Trailhead:

Go 1.5 miles north of the Highway 230/Highway 138 road junction near Diamond Lake. The trailhead parking lot is located along the east side of Highway 138. A USFS Northwest Forest Pass is required to park at this trailhead. Umpqua National Forest Recreation Map reference number is L-6. Located at Township 28 south, Range 5 1/2 east, Section 16.

Attractions and Considerations:

The trail leads through lodgepole pine for the first mile. Timberline is at approximately 7,200 feet elevation. The mountain hemlock-true fir type is predominant. Inviting glimpses of Mount Thielsen are evident as one progresses. A breath taking view of Mount Thielsen presents itself just beyond the Spruce Ridge Trail junction 1.6 miles. As you reach the Pacific Crest National Scenic Trail 2.9 miles, the glacial features of this volcanic peak loom before you. From the Pacific Crest National Scenic Trail, a scramble trail works its way to the spire pointed peak at 9,182 feet elevation. The trail is a steep climb, particularly above timberline beyond which there are no markers. The last 200 feet is a difficult hand-over-hand climb. Elevation gain is 3,782 feet. Hiking boots and caution are highly recommended for climbing on the loose rocky slopes. Those brave and energetic enough to make it to the top, should add their names to the climbing register found there. The view of the east and west sides of the Cascades, from the Sisters to Mount Shasta, is incredible. This trail is used in the winter time by Nordic skiers up to the Pacific Crest National Scenic Trail.

-- Exceprts from: USFS Umpqua National Forest Website, March 2002

To Get There

Mount Thielsen is located near Diamond Lake and north of Crater Lake National Park, in the Umpqua National Forest. There are a store, post office, and campgounds at Diamond Lake. Trails from Oregon Highway 138 lead up to the south and west sides of Thielsen.

-- Excerpt from: Wood and Kienle, 1990, Volcanoes of North America: United States and Canada: Cambridge University Press, 354p., p.191-192, Contribution by David R. Sherrod

Location Map

[Map,21K,InlineGIF]
Southern Oregon Cascades
-- Modified from: Hoblitt, et.al., 1987, USGS Open-File Report 87-297

Useful Links

Umpqua National Forest and Winema National Forest -- U.S. Forest Service websites, scroll to desired Forest
MORE Useful Sites -- CVO Menu, includes links to National Park, Volcano Info, National Forests, Maps, Travel and Tourism Links, Weather, Road Conditions, etc.

For More Information

Mount Thielsen Menu

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04/16/08, Lyn Topinka