Andesite Ridge

We went up to Donner Summit for a morning tour along Andesite Ridge. We gained the south end of the ridge via non-avalanche terrain and then traversed the ridgetop up and over the summit. We descended the E slopes via non-avalanche terrain down to Castle Rd and exited. Along the way ski kicked and stomped on numerous test slopes. The most reactive were in lightly wind loaded NE aspect terrain near treeline at 7,600'. Here there was a thin rain crust buried on Feb 18 with about 18 inches of new snow on top of it. We triggered some cracking down to this crust along with a size D1 avalanche in relatively small terrain.

As we continued to ascend and move up above treeline, moderate amounts of drifting snow were nearly continuous despite the mostly off and occasionally on convective snow showers. In more heavily wind loaded areas, wind slabs were present at 4F to 4F+ hardness over F hard snow. These slabs were very stubborn and difficult to trigger from the edges.

We triggered one size D1 avalanche in small terrain (see attached) on a NE aspect NTL at 7,600'. Cracking up to 18 inches deep was observed in this same area. Cracking went down to the Feb 18 rain crust.