Confidence
Fair - Timing, track, or intensity of incoming weather is uncertain on Sunday
Weather Forecast
Saturday: Dry and cool. Expect sunshine to hit the mountains for the first time in a while. Freezing level 500m. Light north-west winds. Sunday: Moderate precipitation, with the freezing level rising from 1500m to 2000m by Sunday night, when the heaviest precipitation is forecast to fall. 15-20mm. Moderate to strong southerlies.Monday: Light-moderate precipitation, mainly in the morning. Freezing level gradually lowering.
Avalanche Summary
Numerous Size 1-3 slab avalanches (both natural and human triggered) have been reported in the past few days. Skiers accidentally triggered avalanches in Garibaldi Park (Wednesday) and in the backcountry near Blackcomb (Thursday). In both cases they had a lucky escape.
Snowpack Summary
Another 10cm of snow fell last night bringing the total snowfall in the past week to 100-180cm. Weaknesses exist within, and at the base of, the storm snow. New and old wind slabs have formed in exposed NW-E facing slopes, 1m deep in some areas. Cornices have grown large and could act as a trigger for large avalanches. A weak rain crust is found below the new snow up to treeline elevations. This crust may sit on top of buried surface hoar and/or facets. A strong mid pack overlies basal facets that have also gained considerable strength. On average the snowpack is around 200cm deep near treeline. A key concern on Saturday is the forecast sun hitting the new snow for the first time. This could act as a trigger for natural avalanches.
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.