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 -15. 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 south and east of the region may see enhanced snowfall.
Avalanche Summary
A small size 1.0 pocket of windslab was triggered accidentally by a skier on a northeast aspect in the alpine.
Snowpack Summary
Variable amounts of dry facetted surface snow and pockets of surface hoar can be found above the mid-February crust. New melt-freeze crusts can be found on solar aspects at all elevations. The mid-pack is well settled. The late-Jan crust/surface hoar layer can be found about a metre below the surface in deeper snowpack areas. The mid-January surface hoar, can be found below that. These layers have gained significant strength, and chances of triggering these weaknesses have decreased dramatically. 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.