The climb to 8,219-foot Andesite Peak leaves from the same trailhead as Castle Peak and the Peter Grubb Ski Hut, and you can also find access to the Pacific Crest Trail. Those who take the fork to Andesite will encounter much more solitude on this less-popular path and be rewarded with panoramic views of the Sierra from the peak. The route to Andesite is a climb from the beginning, with moderate ascents mixed with some respites of gently rolling slopes. It may be more appropriate for intermediate snowshoers, although there are many areas of gentle backcountry that are easily accessible from the trail and that are ideal for your own wanderings.
The trail follows a dirt snowmobile road, and though snowmobiles are permitted, a number of downed trees and rutted creek crossings on the path tend to make snowmobiles more the exception than the rule here. From the trail fork just after the trailhead, take the left fork. Orange diamond trail markers on the trees mark the trail as it ascends through lodgepole and fir trees. This is the southern slope, and you may see bare patches of earth in sunny areas and near the creek crossings. As you gain elevation and hike farther from the highway, the traffic noise and exposed dirt are replaced by the smell of the pine trees and tracks of martens and squirrels in the snow.
The trail eventually bears northeast and begins to wrap around Andesite Ridge. Snow covers the footpath to Andesite Peak during winter, and because snowmobiles are not permitted up the slope, you may have leave the orange trail markers behind here and blaze your own way up the steep ascent. When you emerge from the trees onto the craggy summit, you'll have a 360-degree view of the Sierra with Sierra Buttes to the west, Castle Peak prominently to the east, and the slopes of Boreal and Northstar to the south and southeast respectively.
To return, it's best to retrace your tracks down the slope to meet up with the snowmobile trail back to the trailhead. It is also possible to return to the snowmobile path and continue northeast to meet up with the Peter Grubb Hut and Castle Peak trails. This trail is not well marked and requires a lot of steep climbs and descents, however, and therefore it is not recommended for those without proper gear and backcountry navigational abilities.
Note that the road to the parking area is steep and can be very icy. If these conditions prevent you from parking at the trailhead, you can cross beneath the freeway and park at the Donner Summit Sno-Park, which will require a sno-park pass. And as with any snowshoe trip near steep slopes, be aware of current avalanche conditions.
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.