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Confidence
Poor - Due to the number of field observations
Weather Forecast
Thursday: Scattered cloud, no significant precipitation. Light variable winds at all elevations. Friday: Broken cloud, 0 to 2 cm of snow possible. Light variable winds at all elevations. Saturday: Few clouds, no significant precipitation. Light N winds at treeline, moderate N/NW winds at ridgetop.
Avalanche Summary
No new avalanches have been reported recently.
Snowpack Summary
10 to 15cm of old storm snow rests upon a thick supportive crust that extends up to around 2200m before changing to a firm wind pressed surface at higher elevations. Winds were out of the NE over the weekend switching to the NW and most recently SW. You may be able to find thin old wind slabs at upper elevations as a result. Below 2200m the crust is effectively capping the snowpack, keeping riders from interacting with deeper weak layers that exist in the snowpack. Two layers of surface hoar can be found down between 50 and 80cm. Recent snow pack test indicate that these layers are unlikely to fail but could propagate widely if they do. At upper elevations where these layers are not protected by the surface crust it may still be possible to trigger an avalanche from a thin or rocky spot. The mid-December crust is becoming harder to find but where it does exist (mainly at treeline elevations) it is over a meter down.
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.