Regions
Vancouver Island.
On Sunday numerous loose dry avalanches were reported as skier triggered on steep west aspects no larger than size one.
Tuesday a skier accidental was reported on a north aspect at 1400 m. The party trigger a size 2 avalanche on a convex roll feature. New snow that had buried surface hoar was then warmed slightly with slab properties becoming present. There was involvement in the avalanche but no injuries or lost gear was reported.
Past Weather
Spring is nearing so its time to pay attention to the rapid effects the sun has on the snow pack. Even a brief period of sun will cause the upper snow pack to become unconsolidated, promoting small avalanches to gain mass and become destructive. The other effect of sun and warming is the rapid settlement of new snow, this can cause new snow to form slabs in a very short time. Clear sky allowed of the development of surface hoar followed by light snowfall that then buried it.
Weather Forecast
A pacific storm system will deliver on Friday to the forecast area, moderate to strong south east wind and moderate snowfall. Prior to this mostly clear conditions with some convective activity will bring isolated snow flurries.Wednesday: 0-5 cm of new snow, Winds Moderate from the North West, Freezing levels to 1000 meters.Thursday: 0-5 cm of new snow, Winds Moderate from the West, Freezing levels to 900 meters.Friday: 20-30 cm of new snow, Winds becoming strong from the South East, Freezing levels 500 meters.
Terrain Advice
Careful and cautious route finding when entering into or over convex rolls or steep features.Test small safe features to determine the bond of new snow on the surface hoar before venturing into anything that requires commitment. Avoid traveling both above and below cornice features.If storm snow amounts exceed 30 centimeters, expect hazard rating to rise to high.
Snowpack Summary
New snow has buried a surface hoar layer that formed during a brief period of cool and clear conditions. On solar aspects the period of warming unconsolidated snow in the upper snow pack began to refreeze overnight forming a crust on steep solar aspects. The mid and lower snow pack is continuing to settle increasing in strength and density.
Snowpack Details
- Surface: New snow overlies surface hoar .
- Upper: A supportive and strengthening bond between the past melt freeze crust down from 15 to 30 cm.
- Mid: A variety of old crusts can be found.
- Lower: Well settled and dense.
Confidence
Moderate - A variety of quality field data and reports with weather models disagreeing on snowfall amounts.
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.