Avalanche Forecast

Issued: Nov 20th, 2015 7:38AM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wind Slabs and Persistent Slabs.

esharp, Avalanche Canada

Purcells.

This bulletin is based on limited observations, mainly from the north of the region. I would tread cautiously this weekend and take the time to gather snowpack information as I go. We always appreciate observations from your day submitted to the MIN

Summary

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

Freezing levels could rise as high as 1500m over the weekend with a temperature inversion developing overnight on Saturday. A cooling trend is expected with the arrival of the next storm system on Monday afternoon. Winds will be mainly light to moderate from the west throughout the forecast period.

Avalanche Summary

The storm earlier in the week resulted in a widespread avalanche cycle that produced some large avalanches. Last weekend there was a MIN report of rider a triggered avalanches on basal facets at treeline in the Dogtooth range near Golden.

Snowpack Summary

Up to 50cm of low density snow fell in the storm earlier this week. A MIN report from the south of the region suggest that some of this fell as rain forming a crust up to 1900m near Kimberley. Moderate westerly winds are likely to have formed pockets of windslab on east and northeast aspects.Below this we're dealing with a complex snowpack. A couple of layers of surface hoar were formed earlier in the month. Where they exist, they are likely to be found buried down 80 to 120 cm. Depending on where you dig, you might also find a couple of crusts. It would be wise to these layers before committing to a slope. Facets are likely to be found just above the ground at higher elevations in the Alpine.Remember that it's still a thin snowpack. Rocks and stumps may be lurking unseen just below the surface. Ride with care!

Problems

Wind Slabs

Westerly wind will have redistributed the low density storm snow from earlier in the week, forming soft windslabs. I suspect that the snow in lee features will be quite reactive. Look for shooting cracks as a sign you are entering a wind loaded area

Be careful with wind loaded pockets>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

A variety of buried persistent weak layers have been reported from across the region including surface hoar and crusts. Although it is starting to look like winter at upper elevations we're still dealing with a highly variable early snowpack.

Now is a good time to dig a snow profile (or two) and figure out how the snowpack changes with aspect and elevation.>Early season hazards such as rocks, trees and stumps are lurking on or just under the surface>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Nov 21st, 2015 2:00PM