The intimidating spire of 9,182-foot Mount Thielsen can be seen as you travel to the trailhead. Yet the peak is not as difficult to climb as it might look. In spite of its appearance, Mount Thielsen is a good choice for beginning climbers and day hikers looking to get on an exposed face.
From the Mount Thielsen Trailhead just off Highway 138 near Diamond Lake, it's a moderate hike to the intersection with the Pacific Crest Trail. The West Ridge Route begins here, and it is a Class II and Class III scramble up scree and slate-like talus to a point called "Chicken Ledge." From this point, it's only 80 feet straight up on Class IV pitch. Many people and teams choose to rope up at this point and use protection. This is not required, but it is a good practice depending on you comfort level. This last 80 feet is on rock that is more solid than in earlier segments, which makes climbing a bit easier.
At the summit you are rewarded with views north all the way to the Three Sisters, south as far as Mount Shasta, and closer views of neighboring Crater Lake and Mount Bailey.
The mountain is also known as the "lighting rod" of the Cascades because it attracts lighting strikes like mosquitos to sugar water. Due to Mount Thielsen's stormy nature, there are a few portions along the trail where small downbursts (microbursts) from thunderstorms have caused larger areas of downed trees. Be vigilant and always be on watch for changing weather.