Ascent of Mount Thielsen on 1979-08-03

Climber: Greg Bramlet

Date:Friday, August 3, 1979
Ascent Type:Successful Summit Attained
Peak:Mount Thielsen
    Elevation:9182 ft / 2798 m

Ascent Trip Report

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

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.

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
Summary Total Data
    Route Conditions:
Unmaintained Trail, Open Country, Exposed Scramble, Rock Climb
    Gear Used:
Rope, Tent Camp
    Weather:Hot, Calm, Clear

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