Developing windslab at Treeline and above on Saturday. 25+ cm possible with incoming storm on Sunday afternoon will increase hazard to High on Monday.
Weather Forecast
Flurries Saturday with mod SW winds . Alpine Temperatures up to -5. Sunday - snow with increasing accumulation through the afternoon with 25 cm possible by early Monday morning, freezing level rising to 2200m then falling to valley bottom as storm passes. Moderate SW winds will accompany this storm.
Snowpack Summary
Cooler temperatures have formed a surface crust from the previous moist snow below 2300m. A persistent slab between 40cm - 200cm thick sits over the Halloween Crust low in the pack. This crust can be found up to 2,700m depending on its location and is between 20cm - 40cm above the ground. Wind slabs likely exist in the upper alpine.
Avalanche Summary
No field patrol on Friday. Thursday had numerous persistent size 2.5 slab avalanches. They failed at treeline and in the lower alpine as a result of warm temperatures, rain and additional snow loading. On Nov. 22nd a field team remote triggered 3 simultaneous size 2 persistent slabs 60-150m away on either side of the wind scoop at parkers ridge.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Sunday
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.