The Christmas Eve Rain Crust (CERC) is creating a tricky, low-probability but high-consequence scenario. Crust thickness is a critical variable. Overall, less rain fell in the Southern Wasatch during the Christmas Rain event, and has left potentially more areas where the crust is thinner, making it easier to impact weak layers near the ground.

We are most concerned with slopes above 9500 feet where less rain fell, and the crust is thinner. The challenge is that we don't have a clear pattern of where those places are. Recent avalanche activity in the Central Wasatch provides clues, but as we enter a storm period, uncertainty surrounding the crust/facet combination remains high. It is a good idea to build in a margin and avoid terrain with characteristics similar to the Sunset Peak avalanche: steep, rocky, wind-exposed.

Looking at the bed surface of the Sunset Peak avalanche is a sober reminder of the consequences of being caught in this type of avalanche right now; the relatively thin veil of snow masks the rock grinder you'd be dragged through.

A snowpit from a Northeast Aspect at 9200 feet. 8 inches of post-christmas storm snow above a 1 inch thick rain crust. Base of the snopwack was 5 inches of moist, rounding depth hoar.

By late day, accumulating snow and moderate SW wind will build shallow soft slabs up to 10 inches thick near exposed ridges. While these surface avalanches will likely be small, they could step down into the deeper, more dangerous hard slab problem (1-3' deep) on upper elevation W-N-E slopes.

'Radiation Recrystallization' (near-surface facets) formed on upper elevation SE aspects over the last few days. While the warm daytime temperatures likely destroyed this layer in most locations, it may survive in isolated pockets and create more sensitive slabs here.