Summary 
| Difficulty | 4 Intermediate-advanced |
| Length | 3.4 miles round trip |
| Starting Elevation |
7200 feet |
| Cumulative Elevation Change |
+1000, -1000 round trip |
| Navigation | Road and map |
| Time | Half day |
| Season | December through mid-April |
| Snowmobiles Use | Low |
| USGS Topo | 7.5' series, Norden |
| Start | The plowed loading zone on the north side of Interstate 80 at the Castle Peak Area and Boreal Ridge exit. Parking is at the Donner Pass Sno-Park located at the east end of the frontage road on the south side of the interstate at the same exit. |
Description
You will find the panoramic views from the summit of Andesite Peak grand. Unlike the easier (less steep) ascent described in the Andesite Peak tour, approaching via the main ridge as described here provides you with many more vistas. It is also a more direct route. Or you can experience the best of both tours by ascending as described here via the ridge and returning via the easier route.
Skier making final ascent along ridge to summit of Andesite Peak
On the summit of Andesite Peak
You will find a short steep section near the beginning of the tour that leads to Andesite Ridge and a much longer steep section that leads to the summit. Along the ridge the timber ranges from nonexistent to heavy. In open areas winds from the west can form cornices on the lee side of the ridge and peak; stay away from the steep edges in these areas.
Easy traveling in an open area before entering dense trees
You can convert this tour into a loop that includes Castle Pass and Castle Valley by intersecting the Andesite Ridge Loop tour to the west of Andesite Peak.
Mileage Log
Numbers in parentheses
correspond to mileage points on map
Waypoint 1 to 2
Miles: 0.0 - 0.3
Elevation change: +100 feet
From the trailhead (1) ski east on the snow-covered road that parallels the interstate and then northwest for a total of 0.3 mile until you reach a road junction (2). The road continuing northwest (straight) leads to Castle Valley, which is closed to snowmobile use, while this tour follows the road to the west (left).
Waypoint 2 to 3
Miles: 0.3 - 0.5
Elevation change: +100 feet
Turn west (left) and follow the snow-covered road for 0.2 mile until you reach a location where you can leave the road to the north (3). There is no landmark here, but the route to the north heads up a drainage between two knobs.
Waypoint 3 to 4
Miles: 0.5 - 0.6
Elevation change: +150 feet
Leave the road and ascend northwest and then north for a total of 0.1 mile until you reach Andesite Ridge (4).
The route up to the ridge ascends the steep section on the camera side of the rock nose in the right of the image
This miner's cabin lies to the southeast on the ridge and just to the northwest of Peak 7605
Waypoint 4 to 5
Miles: 0.6 - 1.7
Elevation change: +650
Follow Andesite Ridge to the northwest for 0.6 mile until the terrain abruptly becomes more steep and then 0.5 mile more to the summit of Andesite Peak (5).
Return to trailhead
Miles: 1.7 - 3.4
Elevation change: -1000 feet
Retrace the route for 1.7 miles back to the trailhead (1).
