Avalanche Forecast

Issued: Mar 31st, 2021 2:00AM

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

Ryan Shelly, VIAC

Vancouver Island.

No new avalanche reported

Summary

Past Weather

Major wind, new snow and Treeline Freezing Level remind us all that Spring has sprung!

Weather Forecast

One more warm day then a reasonable cool down for the Island's mountain ranges as well as a bit of new snow could make for some fun turns with great stability come Thursday! Wednesday: No snow expected throughout forecast area, Winds Light from the SW, Freezing level 1,650MThursday: Less than 5cm snow expected throughout forecast area, Winds Strong from the SW shifting to Light SW winds late afternoon, Freezing level 1,000M and slightly colder for the South (including West and East sides) of the Island forecast area Friday: Less than 3cm Snow expected throughout forecast area, Winds Light from the South (gusting at times to Moderate South winds), Freezing level 900M

Terrain Advice

Major temp increase on Wednesday will excacerbate stability of new storm snow layer and additional cornice growth. Be aware of air temperature increase and signs of unstable snow such as snow melting on trees, pinwheeling and wet surface of snow.Plan routes and choose terrain that is low angle and supportive as you begin to venture into unmodified and uncontrolled snowpack and terrain.Identify and avoid travel either above or below cornice features. Major warmup Wednesday could make them very hazardous.Adjust travel plans to ensure avoidance of slopes during warming events (particularly Wednesday).

Snowpack Summary

Storm events subsided and was replaced with strong to Extreme mountain top winds and reverse loading leaving the downwind areas on a variety of differing aspects. In certain areas, particularly windward terrain, the snowpack was scoured down to firm crusts. The fresh storm snow ended up being found redeposited at much lower elevation due to the extreme wind transport of the snow.

Snowpack Details

Surface: Firm upper snowpack surface softening mid-day with air temperature increase (Northerly Alpine terrain may still hold cold powder snow based on freezing level over last several days
Upper: Well bonded and dense moisture laden snowpack
Mid: Well settled due to melt freeze cycle snowpack has undergone
Lower: Well settled and dense.

Confidence

Moderate - Wednesday will see air temperatures rising yet again (up to 1700M). On Thursday and Friday, forecasted major cooling should create solid consolidation within the upper snowpack.

Problems

Cornices

Cornice failures have the potential to over load the snowpack and trigger both newer snow instabilities as well as deeper instabilities. Expect the new growth to be fragile and when freezing levels rise on Wednesday they will become suspect trigger points for large avalanche events. Location: Many aspects at ridge top in the Alpine and Tree line. Possibility: Triggering of this avalanche problem is possible to likely from light loads such as skiers/snowmobilers. Natural avalanches are unlikely to possible. 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

Loose Wet

Loose wet avalanches could be a factor on Wednesday as air temperatures will rise to the Alpine for the first time in over 72hours. Colder upper snowpack surface will begin to undergo a melting trend for the first time on Wednesday which could result in naturally occurring loose wet avalanches on steep terrain at Treeline and potentially Alpine terrain. Location: Steep unsupported Terrain at Alpine and Tree line. Possibility: Triggering of this avalanche problem is possible to likely from light loads such as skiers/snowmobilers. Natural avalanches are unlikely to possible. Size: If triggered expect these avalanches to be large size 1, on isolated terrain features large, size 2 .

Likelihood

Possible

Expected Size

1 - 1

Valid until: Apr 1st, 2021 2:00AM