Cold and blustery. Winds were moderate, but with stronger gusts. Only a few very light snow showers during the day with no accumulation.
Dec 24, 2022
Lake Basin, Crystal backcountry
|WS-Wet Slab||O-Old Snow||N-Natural||Report|
Dec 28, 2022
|HS-Hard Slab||NC-Cornice Fall||Report|
We also observed 1 older natural cornice fall off of East Peak (E, 6600ft) and what appeared to be buried debris from a wet slide in the same area (East Peak, NNE, 6600ft).
There were plenty of signs of newly forming wind slabs in the terrain: variable new snow depths, scoured slopes, firm hollow drifts, textured surfaces, snow blown out of trees, blowing snow, sharp drifts, and small fresh cornices. Drifts were 4-20 in (10-50cm) deep. These clues indicated direct loading at ridgelines and cross-loading on mid-slope subtle features. Small wind slabs cracked and failed on numerous test slopes. The thinner slabs seemed to be much easier to trigger.
Many of these wind slabs were hard slabs, with skis sometimes barely penetrating the surface.
Cornices: Many typical cornice lines were eroded back from the recent rain and have yet to rebuild. However, where cornices had formed they triggered easily and failed further back than expected.
Below the fresh snow, a newly forming crust was found. This layer was much firmer and more supportive where the wind had scoured the slopes and exposed the older rained-on surface. In these places, it was often 3-4in (~8-10cm) thick and very hard, but still not boot-supportable. Where more snow insulated the crust, it was thicker (8-12in, 20-30cm) but weaker. Below these crusts, wet grains were found for 3-5ft (100-150cm). When our boots punched through the crust, we often plunged to near waist deep.
Ice had formed on most tree trunks and branches during the Christmas weekend rain/freezing rain event.
You could hear creeks running in every valley. Many gullies that were once full of snow, were now open, and water was running fast and high.
I still wouldn't rule out a wet slab or glide avalanche, but we did not make any significant observations or current wet issues.