Observation: Public

Observation Details

Signs of Unstable Snow

Observations

The past few days around Mission Ridge have been been a mixed bag of conditions. We received about 4-5 in of new snow on 12/21, followed by rain up to 6200 ft which was accompanied by strong SW winds. Since the high pressure has set in place following the rain event, we formed a new rain crust that is 2 cm thick and this was followed by a trace -2 in of new snow. Below this rain crust the snowpack remains drys and cold. As of now, surface conditions consist of breakable crust and areas of new wind drifted snow. On 12/22, we observed the new snow being blown around and transported into lee areas creating shallow wind slabs near ridge top.
Looking deeper into our snowpack, our depth greatly varies depending on aspect/elevation. We observed an HS of 35 cm at lower elevations and up top 120 cm at upper elevations. The 12/9 crust is very easily identifiable in quick hand pits and study profiles. We have found rounding facets on top of this crust. We have not seen any buried SH in these locations. Below this crust, we have a fairly uniform structure, but in some locations especially at upper elevations we have found weaker, sugary like snow closer to the ground ( 1- 2mm rounding facets). As noted earlier the depth of this weaker snow varies greatly and it seems unlikely to trigger anything this deep, but worth noting. Overall, it seems like we have elevated hazard at upper elevations near ridge top, especially where new snow has been transported on lee aspects. BTL & NTL there are still many hidden hazards like downed trees and rocks.