Regions
Northwest Inland.
Confidence
Fair - Due to limited field observations
Weather Forecast
Sunday night and Monday: The weakening front should reach the North coast during the night bringing light precipitation over the western part of the region and traces of precipitation during the day and moderate Southeasterly winds. Freezing levels should stay at valley bottom. Tuesday: The ridge of high pressure rebuilds to give place to clearer skies but similar light winds from the Southeast. Temperatures are expected to warm up slightly reaching -4 C in the alpine. Cloud cover should increase later during the day goes as another frontal system approaches. Wednesday: The optimistic models show considerable amounts of precipitation with the coming system and southerly winds.
Avalanche Summary
Minor surface sluffing.(dry loose avalanche) has been reported in the Howson's area.
Snowpack Summary
As a general overview, a shallow snowpack (about 1m deep) exists, with facets that have continued to develop with this week's cool arctic air. Older wind event have scoured some alpine slopes to ground and the forecasted strong Southerly winds for tonight and tomorrow could also redistribute the snow in the alpine and at treeline to create new windslabs. The distribution of these windslabs will be quite variable and some areas were reported to have no wind-effect at all. Indeed, cold density snow is still possible to find at the surface in wind sheltered areas. Below treeline, very loose cold snow is sluffing easily from steep terrain and early season hazards like exposed stumps and rocks are still to watch for. Professionals are still mindful of a facet/crust layer near the base of the snowpack. Although triggering it has become unlikely, it may be possible from a thin-spot trigger point or with a very heavy load (e.g. cornice fall).
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.