Detailed Observation
Date | 2021-02-22 |
Location | Eastern Alaska Range |
Observer | Grant Wilson |
Avalanche | N |
General Observations
Total snow depth: 70cm
Snow profile:
- 1-2cm faceted layer
- 2-35cm unconsolidated “first seasons snow”
- 35cm-55cm hard “pencil” wind slab
- 55cm-70cm recent storm snow
We dug our pit on a 25 degree slope, below a small ridge that split two gully’s which we intended to ski. It was obvious there was loading in the gullys, which is why we dug our pit there.
Results: We found the wind slab at 35cm was highly reactive and failing before we could fully isolate a block to test. The unconsolidated “first seasons” snow (2-35cm) had enough compression to allow the 20cm slab (35-55cm) to be affected by a skiers weight. A final stomp above the snow pit confirmed how reactive the slab was… and our entire pit collapsed at 35cm.
Even on such low angle slopes, we decided we were at a good place to turn around based on the obvious loading which continued above us. Combined with the recent storm snow, failure of the wind slab at 35-55cm could result in catastrophic failure on slopes >25degrees.