New snow, northerly winds and cold arctic air are expected to increase the avalanche danger on Monday.Are you a member of Avalanche Canada? Join today at avalanche.ca/membership
Confidence
Fair - Forecast snowfall amounts are uncertain
Weather Forecast
Cloud developing overnight combined with light southerly winds and freezing levels down to valley bottoms, and alpine temperatures around -10. Mostly cloudy on Sunday with light southwest winds and freezing levels rising up to about 1000 metres. Precipitation starting early Monday morning as cold arctic air descends from the northeast and collides with warmer moist air from the Pacific. Most areas are expected to see 5-10 cm of new snow, some areas in the southeast of the region may see enhanced snowfall.
Avalanche Summary
A skier triggered a size 1.0 steep un-supported pocket of windslab on a northwest aspect at treeline in the Selkirks.
Snowpack Summary
There is quite a bit of variability across the region in regards to new snow amounts. The surface is also variable with everything from dry new snow, loose facetted snow, windslabs, to sun crusts. There is 5-30 cm of facetted new snow and surface hoar above the mid-February crust. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) are generally dormant, and chances of triggering these weaknesses have decreased. However, triggering may be possible with a large input such as cornice fall, or an avalanche stepping down, especially on slopes that see a lot of sun.
Problems
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.
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.