Saturday’s danger ratings are based on intense sunshine and warming affecting the upper snowpack.
Confidence
Fair - Timing or intensity of solar radiation is uncertain on Saturday
Weather Forecast
Saturday: Light W wind. Alpine temperature rising to near 0. Sunny skies, with valley cloud. No snow.Sunday: Moderate to strong SW wind. Alpine temperature near -7. Light snow is possible.Monday: Light SW wind. Alpine temperature near -7. Light snow.
Avalanche Summary
A few small loose dry avalanches have been triggered naturally and by skiers over the last few days.
Snowpack Summary
Recent westerly winds have shifted snow into small slabs on lee slopes. Cornices can be found. An interface buried on Jan 23 is down about 20-35 cm. The nature of this interface varies considerably from place to place. In most locations it appears to be well bonded. Buried surface hoar was found in the north Elk Valley, but this is likely to be a localized problem. The lower snowpack is generally well-settled. Solar warming on Saturday may weaken the upper snowpack. This is expected to be short-lived, with cooler temperatures and cloud forecast for Sunday.
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.