Regions
South Coast Inland.
Wind slabs are slowly gaining strength but you can expect those on south aspects to be touchy. Avalanche danger will rise with the incoming snow Monday night.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Big change is coming with significant snow (and some rain in the south) through to Thursday. MONDAY: Snow beginning near noon with 20 cm in the north (Duffey Lk area) and 30cm in the south (Coquihalla). Winds moderate (25-35 Km/hr) from the southwest. Alpine high temperatures to -2 Celsius in the north and +2 in the south. TUESDAY: In the north: 20-30 cm wet snow, freezing levels 1800m and alpine temperatures near -1. In the south: up to 50mm rain , freezing levels 2700m and alpine temperatures near +5 (!) Winds moderate gusting strong (40-60 Km/hr) from the southwest. WEDNESDAY: In the north: 15-20 cm wet snow, freezing levels 1600m and alpine temperatures near -1. In the south: up to 40mm rain , freezing levels 1900m and alpine temperatures near +4. Winds moderate gusting strong (40-60 Km/hr) from the southwest.
Avalanche Summary
Only a few loose wet natural avalanches (to Size 1.5) were observed on steep solar (south) aspects this weekend.
Snowpack Summary
We have widespread variability in the surface snow conditions due to all the shifting wind patterns, and the sunshine this weekend. The pleasant warm weather this weekend resulted in a sun crust on steep solar (south) aspects. During last week's arctic outbreak, we had 'reverse loading' of storm snow - forming wind slabs on southerly slopes as far down as 1850m in the north (Duffey Lake zone) and 1700m in the south (Coquihalla area). These new, old and variable wind slabs are the primary weaknesses of concern in the snowpack and will likely remain problematic when loaded with the incoming new snow.
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.