Avalanche Forecast

Issued: Apr 7th, 2021 2:00AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Cornices, Wind Slabs and Storm Slabs.

Jesse Percival, VIAC

Vancouver Island.

Avalanche danger ratings reflect the highest danger level expected over the course of the day. No new avalanches reported or observed over the past forecast period.

Summary

Past Weather

Warm daytime temperature and clear sky promoted surface warming on most aspects and elevations. North aspect terrain above 1500 meters may have been saved from the warming effect but freezing levels did rise above 2000 meters for short periods during daytime warming.

Weather Forecast

The weather is changing, a ridge of high pressure begins to deteriorate and a strengthening weather front approaches the area from the north of our region. Models anticipate increasing south west wind and up to 20cm of new snow, with the highest amounts focused on the northern zones of our area. Freezing levels are forecast to remain low. Wednesday: 15 to 20 cm of new snow, Winds Moderate to Strong from the Southwest, Freezing levels 700 meters with a day time a high of 900 meters. Temps at 1500 meters -4Thursday: No new precipitation, Winds variable light to moderate, Freezing levels 200 meters with a day time a high of 500 meters. Temps at 1500 meters -6Friday: 20 to 25 cm of new snow , Winds Strong from the South West Freezing levels 600 meters. Temps at 1500 meters -5

Terrain Advice

Practice patience as new storm slabs will require time to bond to the well formed crust.Choose low angle and well supported terrain.Caution when transitioning into freshly wind loaded slopes.Avoid travel both above and below cornices.

Snowpack Summary

Overall we have a variable snowpack surface. Snow surfaces are a mix of a near impenetrable crusts and on protected north aspects above 1050 meters some dry snow Most of the surfaces Tree line and below have firmed up today and with the forecast new snow arriving, expect sensitive wind slabs to be widespread.

Snowpack Details

Surface: Variable surface conditions, dependent of elevation and orientation.
Upper: reactive crusts at 30 and 100 cm
Mid: Well settled and dense.
Lower: Well settled and dense.

Confidence

Moderate - Generally well aligned forecast models, continued forecaster field observations and both MIN and email public submissions, thank you and please keep those coming.

Problems

Cornices

Cornices are widespread and large. Previous warming and cooling may have added some temporary strength, This problem will persist through the remainder of the season and can be both a trigger for slopes below as well are large enough to create an avalanche hazard alone. Location: Predominantly north aspects at ridge top in the Alpine and Tree line. Possibility: Triggering of this avalanche problem is unlikely to possible from light loads such as skiers/snowmobilers. Natural avalanches are unlikely. Size: If triggered expect these avalanches to be large size 2, on isolated terrain features very large, size 3

Likelihood

Possible

Expected Size

1 - 1

Wind Slabs

New wind slabs will begin to form during snow fall and moderate to strong south west winds. Wind slabs will be forming on old hard surfaces that in many areas are now a melt freeze crust. Expect new wind slabs to be touchy to light triggers, propagate wide and run far and fast. Location: North East thru to North West aspects and found in both the Alpine and Tree line. Possibility: Triggering of this avalanche problem is likely to very likely from light loads such as skiers. Natural avalanches are possible to likely. Size: If triggered expect these avalanches to be large size 2 and in isolated terrain very large size 3.

Likelihood

Possible

Expected Size

1 - 1

Storm Slabs

New Storm slabs are certain to form during periods of snow fall. Storm slabs will be forming on old hard surfaces that in many areas are now a melt freeze crust. Expect new storm slabs to be touchy to light triggers, propagate wide and run far and fast. Location: All aspects and found in both the Alpine and Tree line. Possibility: Triggering of this avalanche problem is likely to very likely from light loads such as skiers. Natural avalanches are possible to likely. Size: If triggered expect these avalanches to be large size 2 and in isolated terrain very large size 3.

Likelihood

Possible

Expected Size

1 - 1

Valid until: Apr 8th, 2021 2:00AM