Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain
Weather Forecast
Two approaching frontal systems will bring warm, wet and windy weather through the forecast period. Thursday: Overcast. Moderate precipitation amounts. Ridgetop winds moderate from the NW. Freezing levels rising to 1900 m. Friday: Overcast. Light-moderate precipitation amounts. Ridgetop winds moderate from the West. Freezing levels 1700 m. Saturday: Overcast. Light precipitation amounts. Ridgetop winds moderate to strong from the West. Freezing levels 1500 m and falling to valley bottom overnight.
Avalanche Summary
On Tuesday, a couple of large, older (past 48hrs) slab avalanches size 2-3 were spotted from the flanks of Albert Peak. Crown depths were approximately 50 cm deep and the suspect failure plane may have been the early April surface hoar. Loose wet natural avalanche activity also occurred on solar aspects up to size 1.5. In neighboring Glacier National Park, skiers triggered a size 3 slab on a buried crust on an east aspect in the alpine on Monday. Last Sunday, a naturally triggered size 2.5 slab failed on a buried crust. With forecast snow and wind this interface may be reaching it's tipping point.
Snowpack Summary
Forecast snow and wind will likely build new wind slabs at treeline and above. Cornices are very large and pose a threat to slopes below.A weak interface down about 60-120 cm consists of a crust on solar aspects, and surface hoar on high-elevation northerly aspects. Recently, very large avalanches occurred in this region and in the neighboring Glacier National Park. The slab above this interface may be reaching tipping point with additional loading.
Problems
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.
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.