Observation: Public

Observation Details

Signs of Unstable Snow

Observations

Remarkably windless day in mission backcountry. Cloudy in morning. Very sunny in afternoon. We dug two pits on E and NE aspects. Interesting conditions requiring thoughtful travel. Lots of bombs going off in the resort this morning and huge avalanche crowns visible from the resort parking lot.

NE aspect pit at 6010. Interested to see new snow interface from 1/4. Also interested in Dec 21/22 crust. HS 140cm. Noticed distinct crust at 90cm and 45cm. New snow failed immediately in a shovel tilt test. Shear test produced failure @ 123cm Q2-RP. Seemed to fail on weak snow rather than a distinct crust. CTE-1-BRK @ 123cm. CTE-8-SP @ 90cm (12/21 crust)!!

E aspect pit at 6190. Interested to see new snow interface from 1/4. Also interested in Dec 21/22 crust. HS95. Distinct crust at 70cm and 30cm. Faceted snow from 30cm to ground. Shear test produced failure @ 65cm. Q2-RP. Failed on weak snow on top of crust. CTE-1-BRK @ 80cm (12/21). CTE-5-RP @ 70cm. CTM-8-SC @ 30cm on depth hoar resting on the ground.

The results were scary enough that we chose very conservative ski terrain for the day.

Scary layers lie deep below the snow surface. While the deep layers may not be immediately reactive, if you trigger one you’re gonna have a bad time. These layers need time to heal. Travel with caution.