Keep an eye on the temperatures over the next few days. Solar radiation and rising freezing levels can weaken the snowpack and make destructive avalanches more likely.
Confidence
Fair - Due to the number of field observations
Weather Forecast
Mainly sunny skies will persist throughout the forecast period as the dry ridge continues to occupy our province. Daytime freezing levels should hover around 1500m for each day, although an inversion is possible on Tuesday. Winds will remain generally moderate from the northwest.
Avalanche Summary
Avalanche activity has gradually tapered off throughout the week. On Thursday there were a couple reports of natural cornice falls, but these did not trigger slabs. There was also a report of a size 1 (20 cm deep) skier controlled wind slab from an East facing slope. Wind slabs could build and remain sensitive to rider triggering throughout the weekend.
Snowpack Summary
Light amounts of recent snowfall (5-15 cm) covers the previous variable snow surface of surface hoar, crusts, dry facetted snow, or wind affected snow depending on aspect and elevation. The "Valentine's Day" crust is just below the surface and is now strong and thick in most places. New wind slabs may have formed in lee terrain from recent W-NW winds, and cornices remain large and weak. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) continue to give variable results in snowpack tests. Chances of triggering these weaknesses have decreased, but triggering may be possible from thin or rocky snowpack areas; or perhaps with a cornice fall, or an avalanche stepping down, especially on sun drenched slopes.
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.
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.