Avalanches and Deep Snow on Andesite

Our day consisted of skinning uphill on low angle slopes in knee to thigh deep snow, seeing some avalanche activity on steeper slopes, and skiing back down our low angle skin track. As soon as we started breaking trail through deep snow, we saw some cracking as a soft storm slab broke on a slightly less dense layer of storm snow about 12 inches below the surface. We avoided any slopes steeper than about 25 degrees as we worked our way up into more open terrain. 

We approached a larger NE-ENE facing slope at 7850 ft. with some wind exposure from low angle terrain that lead up the backside of the slope. It had a small wind lip near the top of the slope. We stayed well away from the edge of the slope. We also made sure that no one could be below us on the slope. Then we kicked the snow near the wind lip while standing where we knew solid rock existed below us. That kick triggered a soft slab avalanche that behaved like a mix of a wind slab and a storm slab. It ran to the trees at the bottom of the slope and measured 18-24 inches deep and about 50 ft wide (see photos). It entrained enough snow to bury a person.

As we moved into more exposed terrain above, we found an E facing test slope at 8090 ft. with more exposure. A ski kick and cut at the top of this slope also produced a similar avalanche (video). 

We chose to return via our low angle skin track.

We also searched for evidence of the weak layer near the crusts in the old snow, but we could not find it in this area.