Avalanche Forecast

Issued: Mar 8th, 2021 1:00AM

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

Jesse Percival, VIAC

Vancouver Island.

On Friday, North aspect terrain produced two natural size three windslab avalanches between 1300 and 1500 meters. Avalanche control teams at Mount Washington utilized explosives to trigger numerous size 2 windslab avalanches. Skier trigger size 1 windslab avalanches continued to linger and reported on north west facing terrain just below 1300 meters on Sunday.

Summary

Past Weather

A significant storm event delivered on average over 100 centimeters of snow combined with strong South west wind. The western leading edge of the island mountains received over 150cm of new snow. Temperatures remained cool with freezing levels reaching 1200 meters but mostly stayed below 1000 meters.

Weather Forecast

Initially unsettled weather will bring clouds and light snowfall. By Tuesday evening a ridge of high pressure will bring clear sky and no new precipitation. Monday: 1 to 5 cm , Winds Moderate from the South East, Freezing levels at 500 meters rising to 600 meters.Tuesday: Trace amounts of snow, Winds light to moderate from the South East, Freezing levels at sea level with a day time high of 600 meters.Wednesday: No new precipitation , Winds Light to Moderate from the North West, Freezing levels at seas level with a daytime a high of 1000 meters.

Terrain Advice

Caution when transitioning into terrain with recent wind loading and steep convex roll features.Avoid direct solar terrain during periods of sunshine and daytime warming.Caution above or below cornice features, recent loading has continued to build upon already very large cornices.

Snowpack Summary

Storm snow amounts between 80 to 150 centimeters has been transported by the wind and can be found on North west thru to North east aspects. This new load of snow has begun to settle and overlies a previous crust surface and has either naturally released during the storm event or is moderately bonding.Terrain exposed to the wind is stripped and scoured. The persistent slab from February is now down over 200 centimeters and is dormant and currently non reactive to testing . Below the snowpack is dense and well settled.

Snowpack Details

Surface: A variety of surfaces, new low density snow, wind scoured at upper ridge tops and wind loaded on north aspects.
Upper: Settling new snow between 100 and 150 centimeters.
Mid: Old unreactive crusts, overall dense and well settled.
Lower: Well settled and dense.

Confidence

Moderate - Forecaster field observations and numerous reports. No alpine observation, uncertainty with alpine windslab stability .

Problems

Loose Wet

Clear sky and sun will cause the surface snow to become unconsolidated. **Location:** Specific to steep Solar aspect terrain and at all elevations. **Possibility:** Triggering of this avalanche problem from light loads such as skiers is likely to very likely. Natural avalanches are likely. **Size:** If triggered, expect these avalanches to be small size 1 but could gain mass and push a traveler into a terrain trap.

Likelihood

Possible

Expected Size

1 - 1

Wind Slabs

Found on predominantly North aspects. This avalanche problem was formed during the past storms strong south west winds. Caution on feshly loaded slopes, this problem, if triggered has the potential to create very large avalanches. **Location:** North East thru to North East aspects and found in both the Alpine and Tree line. **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 large size 2, and on isolated terrain features very large, size 3 .

Likelihood

Possible

Expected Size

1 - 1

Valid until: Mar 9th, 2021 1:00AM