This wind slab problem is on the surface and is easy to identify. Shooting cracks, or firmer snow are slab indicators. Dig down and investigate the upper snowpack before committing to your line.
Weather Forecast
Sunny with cloudy periods, no precipitation, light winds from the NW and the freezing level will rise no further than valley bottom. Snow beginning tonight(flurries), 7cm on Tuesday and 13cm on Wednesday. This brief system does not last long, or pack much punch as another ridge of high pressure follows closely behind.
Snowpack Summary
25cm of storm snow overlies a wide variety of surfaces depending on aspect, elevation, and drainage; including but not limited to surface hoar in sheltered locations to unreactive wind slabs in the alpine. The new snow was accompanied by extreme winds on Saturday, forming slabs in specific areas throughout the park.
Avalanche Summary
A size 1 skier accidental and a size 2 skier controlled occurred yesterday. The size 1 was on a east aspect, 40 deg slope at 2450m in Hospital Bowl. The slab was 15-25cm deep, 30m wide and ran for 100m; the size 2 was in the lookout couloirs. Another similar avalanche occurred on Saturday in the Ravens; size 1.5 at 2100m on a SW asp, 35 deg slope.
Confidence
Due to the quality of field observations
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.