Winds are redistributing the recent snowfall into slabs on lee slopes. Careful terrain selection and route finding are important for safe back country riding.
Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Precipitation should taper off late today ( Sunday) and give the Sea to Sky region a somewhat sunny Monday and Tuesday. Freezing levels should stay close to1500m, for the rest of the week. Little precipitation is expected until Thursday.
Avalanche Summary
Reports from yesterday tell of a few size 1 storm slabs, wind slab and loose-wet avalanches. Explosive testing has produced few results
Snowpack Summary
The snowpack is generally strong and well settled with 10 cm of new snow overlying a variety of melt-freeze crusts on solar aspects in the alpine as well as lower elevations. Old wind slabs and surface facets may still still exist on high north facing slopes. The recent storm with strong winds has scoured windward slopes down to the old crusty surfaces and developed wind slabs on lee slopes. Solar aspects are moist during the day and forming crusts at night. Cornices continue to grow and may become weak with daytime warming.
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.
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.