Observation: Scott Hill

Triggering a slab avalanche on a PWL—the weak snow below the Christmas Eve Rain Crust (CERC)— is unlikely (but not impossible). Snowpit tests left us with letters and numbers as results, but the fact of the matter is that in most locations, the CERC is stout and supportable enough to not allow for a rider to trigger an avalanche on the weak snow below the surface. The new snow above the CERC, which has had varying success bonding across the Salt Lake zone, is the main concern for triggering avalanches.

As Drew would say, THE FINE PRINT: concerningly weak snow still exists at the base of the snowpack. Mack and I observed easy fracture initiation on weak snow at the ground on one compression test (CT6), but then got both no initiation or propagation on one ECT (ECTX)...before receiving an ECTP30 with full propagation at the ground on a second test. Scratching your head? Exactly. This, along with all obs since the CERC was buried, and recent activity (or lack there of) on the PWL leads us to conclude that it is unlikely to trigger a PWL avalanche on most slopes. However, if you find the wrong spot, most likely in high, rocky, thin, northerly terrain, it remains possible.

While the wind yesterday and today certainly transported new snow and built fresh wind deposits (see photos below), the new snow appeared to be bonding moderately well. All deposits we observed above ridgeline were soft in character and unreactive. We did not get a single crack or collapse while stomping along on wind pillows. While I believe the slickness of the CERC will be host to reactive wind slabs in pockety terrain elsewhere, we did not observe these in our travels along the PC Ridgeline—which was a surprise to us. We also noted that despite the amount of new snow, there was less snow available for transport even with sustained loading speed winds, likely due to the density of the snow and the temperature it fell at.