Regions
Vancouver Island.
Size 2 avalanche (including a partial burial) Mt Cokely, initiated Saturday March 20 on North Facing Convex feature at higher elevation. Additional reports (South Island) of unstable snow and new storm snow in excess of 30cm.
Past Weather
A series of stormy and relatively cool winter days have deposited new snow on a variety of snow surfaces throughout Vancouver Island.
Weather Forecast
Monday: Less than 1cm Snow throughout forecast area, Winds Moderate from the NW shifting to Light NW winds in late afternoon, Freezing level 1,050MTuesday: Less than 2cm snow throughout forecast area, Winds Moderate from the SW shifting to Light SW winds in afternoon, Freezing level 1,000MWednesday: 10cm snow to 20cm Snow. Winds Moderate from the NW (gusting to Strong), Freezing level 1,050M.
Terrain Advice
Practice patience and allow time for new storm instabilities to stabilize prior to committing to any steep terrain.Plan routes and choose terrain that is low angle and supportive as you begin to venture into unmodified and uncontrolled snowpack and terrain.Identify and avoid travel either above or below cornice features.Adjust travel plans to ensure avoidance of slopes during warming and where rain events may occur at the Below Treeline elevation band over weekend.
Snowpack Summary
Mt Washington reporting a total storm snow accumulation of 50cm. Other areas have received similar amounts (30+ cm's) of snowfall over this past weekend's storm event. The upper snowpack at lower elevation (Below Treeline) was subjected to a melt freeze event on weekend however higher elevation bands (upper Treeline and Alpine) have 2+ feet of soft powder snow conditions resting on top of firm snow.
Snowpack Details
- Surface: 50+ cm of new powder snow conditions at Treeline and Alpine elevation bands
- Upper: Well bonded and dense moisture laden snowpack
- Mid: Well bonded midpack
- Lower: well settled and dense
Confidence
High - Weather models in agreement. Sufficient Professional and public observations. Thank you Faron, Evan and Derek for your MIN reports!
Problems
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.
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.