Avalanche Forecast

Issued: Mar 16th, 2020 2:00AM

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

Jesse Percival, VIAC

Vancouver Island.

A few natural avalanches where reported from last week, Friday ski cutting on steep terrain produce size one loose dry avalanches to size one. Overall the snow-pack tightened with no reports or observations over the past weekend.

Summary

Past Weather

Cool temperatures and strong North wind prevailed over the past forecast period.

Weather Forecast

Clear conditions are expected to continue with a rapid rise in both temperatures and freezing level forecast.A strengthening high pressure system will push the storm track to the south of the forecast region.Monday: No new snow, Winds Light from the North, Freezing levels to 2500 meters.Tuesday: No new snow, Winds Moderate from the North, Freezing levels to 2200 meters.Wednesday: No new snow, Winds Light from the West, Freezing levels 800 meters.

Terrain Advice

Avoid avalanche terrain during periods of high hazard.Provide a wide berth to cornices and avoid travelling either above or below them. Choose low angle terrain and review route selection and objectives to ensure minimal exposure to overhead hazard.

Snowpack Summary

Clear and cool conditions have provided an ideal environment for surface hoar to grow and can be found at all elevations and aspects on terrain that is protected from the wind and sun. Strong north winds have continued to scour and redistribute any available snow to south aspects. Areas that have been undisturbed by the wind continue to provide excellent skiing and riding conditions. The mid and lower snow pack continues to gain strength and settle during the past period of cool and consistent temperatures. On solar aspects periods of clearing and warming unconsolidated the upper snow pack. Daily unconsolidated snow in the upper snow pack began to refreeze overnight forming a crust on steep solar aspects.

Snowpack Details

Surface: A variety of surface conditions exist that include, Moist surfaces on solar aspects, surface hoar, wind scoured, and wind loaded in areas that are directly lee of winds.
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

High - Forecast models all agree on warming temperatures and rising freezing levels.

Problems

Cornices

Found on predominantly North aspects, large to very large cornices can be found. expect these features to become weak with the influence of warm air and have the potential to fracture, especially around rock features and other dark areas that can collect and harbor heat. **Location:** North aspects ,found at ridge tops and peaks in the Alpine and at Tree line. **Possibility:** Triggering of this avalanche problem is possible to likely from light loads such as skiers. Natural avalanches are possible. **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

Loose Wet

This problem will become wide spread once freezing levels and temperatures begin to rise. Expect to find the most problematic areas to be on steep slopes that face the sun. **Location:** All aspects and elevations **Possibility:** Triggering of this avalanche problem is likely to very likely from light loads such as skiers. Natural avalanches are likely to very likely. **Size:** If triggered expect these avalanches to be small, but will have the potential to gain mass and become large size 2 . Within isolated large terrain features, expect this problem to be very large, up-to size 3.

Likelihood

Possible

Expected Size

1 - 1

Wind Slabs

Found on predominantly North aspects, but can be found on south aspects from past North wind. Wind slabs have buried a variety of surfaces including, surface hoar interface and melt freeze crust. As temperatures increase rapidly settling snow may cause winds slabs to become increasingly sensitive to human triggering. **Location:** All aspects and found in both the Alpine and at 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 on isolated terrain features very large, size 3 .

Likelihood

Possible

Expected Size

1 - 1

Valid until: Mar 17th, 2020 2:00AM