Avalanche Forecast

Issued: Mar 31st, 2017 4:31PM

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

mbender, Avalanche Canada

Kootenay Boundary.

Cloud cover with higher freezing levels may continue to add warmth to the snowpack and keep the recent storm snow reactive

Summary

Confidence

Moderate - Freezing levels are uncertain on Saturday

Weather Forecast

SATURDAY: Cloudy with isolated flurries / Moderate southwest wind / Alpine temperature -2 / Freezing level 1600mSUNDAY: Mix of sun and cloud / Light to moderate northwest wind / Alpine temperature -4 / Freezing level 1200mMONDAY: Mix of sun and cloud / Light north wind / Alpine temperature -4 / Freezing level 1200m

Avalanche Summary

Reports on Thursday indicate several natural avalanches running during a warming event to size 2.5 and 3. These were triggered on the March 21 melt freeze crust by cornice falls and a skier triggering a smaller avalanche that subsequently stepped down to the crust. They were running on northerly aspects in the alpine and tree line elevation bands. One report from Wednesday detailed a size 2 remotely triggered avalanche running on the same crust. This ran on an east aspect at 1900m and was 50cm deep.

Snowpack Summary

A series of snowfalls throughout the past week accumulated roughly 60-90 cm of moist new snow in the region. Periodic high freezing levels and solar exposure over the same period has formed a variety crusts within and/or on the surface of the storm snow up to 2000m. This all overlies a rain crust that was buried on March 21 up into the alpine. This crust is reported to be recently reactive to heavy loads. At upper elevations, above 2100m approximately, the late and mid-February persistent weak layers (100-150cm down) and basal facets in shallow snowpack areas may still exist. There is no recent information on the presence or reactivity of these persistent layers. For this reason it would be prudent to investigate their presence if traveling in the highest alpine areas of the region.

Problems

Storm Slabs

Recent snow accumulations and wind have developed reactive storm slabs in the alpine and at tree line.

Be cautious as you transition into wind affected terrain.A heavy load caused by a cornice failure or a small avalanche could trigger deeper weak layers

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Warm spring days with high daytime freezing levels and potential sun may continue to result in loose wet avalanches.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.