Weather Forecast
Tonight and Sunday: A weak disturbance is forecasted to bring mainly cloudy skies, a possibility of light precipitation with light N-NE winds, freezing levels at 500 m. and alpine temperatures around -10 C.Monday: A similar situation is forecasted for early Monday but should give way to partly cloudy skies during the day with light N winds and surface freezing levels. Tuesday: A ridge of high pressure is gaining strength bringing dry and cold temperatures.
Avalanche Summary
Several natural loose dry avalanches size 1 and 2 were reported on S and N aspects in the Coquihalla area.
Snowpack Summary
In the Southern part of the region, the recent storm snow has been redistributed by light to moderate winds from the SW to the N to create soft slabs in the alpine and at top of treeline. Warm temperatures at the beginning of the storm have created a good bond between the new snow and the crust. This new snow would also be sitting on a surface hoar layer on N aspects below treeline.In the Northern part of the region, 5-10 cm of recent snow has fallen over various surfaces, hard windslabs in the alpine, suncrust on S aspects and surface hoar in sheltered areas. There continues to be a concern for deeply buried layers of weak facetted crystals, this is mostly a concern on slopes with a shallow and variable snowpack in the Duffey Lake and Chilcotin areas.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.