Quick report
- Cracking
- specific
- Collapsing
- isolated
We arrived at Donner Summit at 12:30 pm to about 3 inches of new snow in wind-sheltered areas. When we departed the area 3 hours later, this new snow amount in wind-sheltered areas had increased to 6 inches. We saw signs of instability associated mainly with the Jan 2 PWL in several areas both above and below treeline where buried surface hoar was a part of the Jan 2 PWL. We saw some moderate but overall limited amounts of wind loading with minimal signs of instability associated with wind slabs failing at or above the old/new snow interface. The persistent slab avalanche problem was the major player at work.
We mainly traveled on E aspects today. We triggered long cracking on the Jan 2 PWL in several areas. We triggered short cracking on a very thin new crust at the old/new snow interface in numerous areas. We triggered a slope scale collapse on the Jan 2 PWL in one location (E aspect, 8,050', NTL).Weather
- Cloud Cover
- overcast
- Wind Loading
- moderate
- Recent Snowfall
- 15
- Snow Avail For Transport
- moderate amounts
Snowfall rates observed at S2 to S3 during our time in the field from 12:30 pm to 3:30 pm.
Snowpack
The surface hoar layer buried on Jan 2 continues to lurk 12 to 18 inches below the surface. This layer rested on top of a firm crust on E aspects. We also saw a thin crust with small facets around it at the base of today's storm snow. This thin crust likely formed yesterday due to localized fog/mist on Donner Summit. We saw instability on both of these layers (see instability comments).