The secondary peaks that rise around Lassen Volcanic National Park offer bountiful options for backcountry skiing. One of the standouts, 9,087-foot Mount Diller, is a prominent peaklet that rises from the ridge that runs between 10,457-foot Lassen Peak to the northeast and 9,235-foot Brokeoff Mountain to the southwest. Formerly part of a larger stratavolcano known as Mount Tehama, Mount Diller’s eroded features offer some fantastic skiing descents, including a steep 400-foot chute on Diller’s southwest aspect.
The most direct ascent to Mount Diller is from the park’s southwest entrance at the Kohm Yah-mah-nee Visitor Center. Leave your car at the visitor center, a popular departure point for cross-country skiers and snowshoers heading up the Lassen Park Road (Highway 89). The highway is unplowed and closed to vehicles in the winter.
From the visitor center, begin skinning up the Lassen Park Road for a mile to the Sulphur Works parking area. Sulphur Works is located on the east side of the bridge that crosses West Sulpher Creek. The Sulphur Works area contains numerous fumaroles and steam vents, a peculiar sight in the otherwise wintry landscape. Use caution while skinning around the Sulphur Works zone and give yourself a wide berth around any fumaroles.
From the Sulphur Works area, head uphill to follow the Ridge Lakes summer trail that stays to the right of the creek. Depending on snowpack, you may have to cross the creek further uphill via a snowbridge; typically the creek is buried in snow at higher elevations.
If you are out for a day tour, continue climbing through glades toward the south face of Mount Diller. After emerging from the trees, Diller’s southwest chute will come into view. Ascend the open slopes trending east toward the Mount Diller-Pilot Pinnacle saddle. From the saddle, skin up Diller’s east ridge until it steepens and demands a bootpack to reach the summit ridge. The views from Diller's summit ridge of Lassen's mountainous backdrop are outstanding and reveal countless ski descent options on Lassen Peak and the surrounding peaklets.
The southwest chute descent is obvious from the summit ridge and forms great corn around midday during freeze-thaw cycles. During powder conditions, make sure to check for stability. This south facing terrain is also prone to loose, wet slides from the sun exposure. Follow your descent skin back up the saddle for another ski option or head back down the way you came up. The glades on the south aspect below the saddle also offers some fun and varied terrain to explore en route back to the highway.
In addition to the southwest chute, Mount Diller has enticing bowls on the north aspects. Pilot Pinnacle, which is reached by heading east up the ridgeline from the saddle, also has some great north-facing bowls. If you are planning an overnight trip, the Ridge Lakes area is located 2 miles from the car park, and is an excellent winter base camp. From here you can farm other lines on Diller's south face or explore off of the ridge that rises above the lakes. A fall line ski down Diller's southwest chute and the bowl below puts you in line with Ridge Lakes.
Winter backcountry adventures can be dangerous outdoor activities that pose significant risks as conditions affecting safety (i.e. weather, snowpack stability, avalanche hazard) are constantly changing. Prior to engaging in these activities each individual should get the proper training to make safe decisions and be equipped to use avalanche safety resources and tools. Please visit our Backcountry Skiing and Avalanche Safety post to learn more.