Observation: Public

Observation Details

Observed Avalanches

Signs of Unstable Snow

Observations

Weather- Overcast skies w a few brief cloud breaks. Moderated NW-N wind with moderate to intense blowing snow at ridgetops. Air temperature in the mid 20's F. Moderate (S2) snowfall in the morning, tapered by midday, and then heavy (S5) snow from 15:00-16:00.

Snowpack- By the end of the day there was 30cm of snow in the past 24hrs above 4,500ft. Snow surfaces stayed dry above 4,000ft on most aspects. On slopes that stayed in the shade over the past two days, there was about 55cm of dry snow above the 4/7 crust. This varied with elevation and exposure to sun. The 4/9 interface was variable, as was the bond to the most recent snow. On wind-sheltered and shaded slopes that were less than 40 degrees, the bond at the new/old interface was generally good. In steeper, sun-exposed, and wind-affected terrain, the new snow slid easily. In a profile at 5,550ft on a NE aspect, we found mostly dry snow with 4 thin crusts from the past month in the top 1.5 meters (5 feet) of the snowpack. The mid-January weak layer was about 280cm below the surface and the total height of snow was over 500cm (15 feet!)

Avalanches and signs of instability- We saw a handful of small (D1) loose dry avalanches on northerly slopes steeper than 40 degrees. Aside from those mentioned above, others were about 10cm deep and had run in the early morning hours within the recent snow. On leeward, E aspects of a ridge at 5,500ft we were able to easily trigger slab avalanches on very small features in wind drifted snow. The slabs were about 25-30cm deep and ran on a crust that formed on the 9th. We observed cracking in these areas, but not elsewhere.