Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
The arrival of the next frontal system should come Monday night into Tuesday bringing light-moderate snowfall amounts which will intensify later Tuesday. Tuesday: New snow 15-25cm. Ridgetop winds 70-80km/hr from the West. Treeline temperatures near -2, with freezing levels up to 1200m. Wedneday: Snow amounts 5-10cms. Ridgetop winds from the NW 55-75km/hr. Freezing levels falling to valley bottom. Thursday: Trace amounts. Moderate NW ridgetop winds.
Avalanche Summary
Most recent avalanche activity has been a size 2 natural that occurred on a NW aspect @ 1900m. The depth was 50-55cm, 70m wide and running on a buried facet layer. There was also a size 2 skier triggered avalanche in the Blackcomb backcountry (outside the ski area boundary). This was on a North aspect @ 2300m. No burials or injuries reported. Several small size 1-1.5 skier triggered slides have also been reported. I suspect there will be an increase in avalanche activity with the forecast wind and snow. It may be a good time to wait out the storms until the new snow has a chance to settle out and bond.
Snowpack Summary
Heavy snowfall and strong winds on Friday night created new wind and storm slabs and continued to cover an assortment of old snow surfaces. These old surfaces are now 30-45cm down and include crusts that exist on all aspects at lower elevations and on steep solar aspects higher up. Facets (sugary snow crystals) and spotty surface hoar (feathery snow crystals) may also exist in combination with crusts, so there may be continued slab reactivity at lower elevations. With more snow and wind in the forecast the new load may have a poor bond to the underlying buried surfaces. The mid and lower snowpack are strong and well settled. The average treeline snowpack depth is about 240cm.
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.