Confidence
Fair - Timing, track, or intensity of incoming weather is uncertainfor the entire period
Weather Forecast
Monday: 10-12cm of snow arriving late in the day / strong southwest winds / freezing level at 1400mTuesday: moderate to heavy snowfall throughout the day / strong southwest winds / freezing level at 1400mWednesday: moderate snowfall / strong south winds / freezing level at 1400m
Avalanche Summary
In the past 24 hours explosives testing in the region produced numerous slab avalanches up to size 2.5 (one of which stepped down to the october crust on a steep, unsupported feature in the alpine. There was also a size 2.5 skier remote (triggered from a distance) avalanche near Pemberton at the 1600m elevation. This avalanche was about 125cm deep and is thought to have ran on the rain crust mentioned in the Snowpack Observations column.
Snowpack Summary
The total snowfall in the past week has amounted 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. Although the break in the weather this weekend has given the upper snowpack some time to stabilize, the avalanche problem in the upper snowpack is still very real and will continue to be with the forecast wind and snow.In the mid snowpack a weak rain crust is found below the new snow up to treeline elevations. This crust, which has recently produced large avalanches, may sit on top of buried surface hoar and/or facets.A strong lower pack contains facets and and an associated crust that have also gained considerable strength.On average the snowpack is around 200cm deep near treeline.
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.