Avalanche Forecast

Issued: Apr 4th, 2017 8:00AM

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

Parks Canada percy woods, Parks Canada

Danger levels will increase with prolonged solar input through the day. Pay attention and avoid exposure to large cornices overhead.

Summary

Weather Forecast

A mix of sun and cloud today with no precipitation forecast.  Freezing level of 1600m and an alpine high of -5C.  More unstable weather is forecast to invade for the rest of the work week with rising freezing levels and upwards of 20cm of snow by Friday evening.

Snowpack Summary

Upwards of 30cm of storm snow in the alpine over the weekend. SW winds in the moderate range have moved the storm snow onto alpine lee features forming soft slabs. Cornice failures pack a big enough punch to trigger deeper weak layers in the upper snowpack. Test pits producing easy to hard resistant planar results in the top 60cm of snowpack.

Avalanche Summary

One new size 2.5 slide observed off Mt MacDonald's north face yesterday. Also a report of a remote trigger of cornice off the Jupiter traverse that triggered a size 2 down to rock on the east face of Castor. The slide ran down to the glacier bench below. Several skier accidental slides and skier cut slides to size 2 from Sunday observed up Balu.

Confidence

Due to the number of field observations

Problems

Wind Slabs

An icon showing Wind Slabs
Last weekend's storm snow has been redistributed into widespread soft windslab in the alpine down to treeline. These slabs need time to bond to the old snow surface. They may prove more reactive with prolonged solar input.
Use caution in lee areas. Recent wind loading has created wind slabs.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices
Large cornices hanging along lee ridge lines are fragile and pack a major punch if they fail onto the slopes below. Cornices have potential to trigger deeper weak layers and cause very large avalanches. Solar input will increase chance of failure.
Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Give cornices a wide berth when traveling on or below ridges.

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 5th, 2017 8:00AM