Observation: Public

Observation Details

Signs of Unstable Snow

Observations

Toured around Kendall today. Started out under overcast skies with light to moderate snowfall, which transitioned to broken skies, no precipitation, and some sunbreaks filtered through high clouds in the afternoon. The new snow was relatively low density for this zone in the morning, but getting heavy by mid-afternoon in open areas and at lower elevations. When the sun was out, it was quite strong. Encountered a graupel shower just before leaving the parking lot at 3:30.

No signs of recent avalanches, although we did run across rollerballs below rockfaces at ~3800' on our way out at 3:00 or so. No signs of recent wind transported snow, which was a bit of a surprise. Test slopes did not reveal shooting cracks or other signs of instability, and hand shear tests suggested the new snow was not prone to failing in blocks. The only somewhat concerning observation we noted was in steeper terrain above treeline, where the top few inches of new snow was failing in isolated small and shallow soft slabs triggered by skiers traversing. These very small slides did not entrain more snow or run more than a few feet, were not widespread.

Dug a pit at 2:00 p.m. on a W aspect above treeline at 4990' in open slopes on Kendall. Found 41cm of new snow on the 3/31 crust, with the 3/22 crust down 66cm from the surface. Shovel tilt tests highlighted an interstorm density change 26cm from the surface. This same layer 26cm down failed in compression tests (CTE BRK). Interestingly, the 3/31 crust at 41cm down was not reactive in compression tests, but the deeper 3/22 crust at 66mcm down was (CTM RP).