Avalanche Forecast
Issued: Feb 17th, 2020 1:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
Jesse Percival,
VIAC
One small natural loose dry avalanche reported on a North aspect at tree line. No other observations or reports.
Summary
Past Weather
Over the past forecast period the region experienced a couple of weaker pacific storm fronts that delivered snowfall storm amounts of 5 to 10 cm on the eastern dry side of the island to 25 plus cm’s of snow on the leading western edge west side. Wind was light to moderate from the south west with periods of clearing and sun.
Weather Forecast
A pacific high pressure system will anchor to the north of the island over this coming forecast period. Expect Clear and sunny sky, very little precipitation and overnight cooling with freezing levels dropping to near seas level. Daytime freezing levels are expected to reach 1000 meters during mid-day.Monday: Trace amounts of snow, Winds Strong subsiding to moderate from the North West, Freezing levels to 1000 meters.Tuesday: No new snow, Winds Moderate from the North West, Freezing levels to 1000 meters.Wednesday: No new snow, Winds Moderate from the South East, Freezing levels 900 meters.
Terrain Advice
New, freshly formed wind slabs from North winds will be initially touchy to light triggers, caution and avoidance techniques should be enacted when entering terrain lee to the wind and just below ridge tops. Careful and cautious route finding when entering into or over convex rolls or steep features.Avoid traveling both above and below cornice features.
Snowpack Summary
Past wind has scoured exposed ridge top and exposed terrain down to the January 31st melt freeze crust. This crust is supportive to skiers but not supportive to foot penetration. In areas protected from wind scouring, the January 31st melt freeze crust can be found down as deep as 30 cm and is bonding moderately well. The mid and lower snow-pack is well settled and dense with a few interfaces that are not concerning but are still detectable.
Snowpack Details
- Surface: Variable surfaces conditions from wind loaded to wind pressed and on solar aspects a breakable sun crust.
- Upper: A supportive and reactive 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 - Good data, both telemetry and field. Forecast models are in agreement.
Problems
Wind Slabs
Available low density snow and wind has and will continue to transport snow to predominantly North aspects. During this forecast period, expect reverse loading and new wind slab to form on South aspects as a result of the Strong North west wind.
**Location:** All aspects found in both the Alpine and at Treeline.
**Possibility:** Triggering of this avalanche problem is possible from light loads such as skiers. Natural avalanches are unlikely.
**Size:** If triggered expect these avalanches to be small, and on specific terrain features large, size 2.
Likelihood
Expected Size
Valid until: Feb 18th, 2020 1:00AM
