Avalanche Forecast

Issued: Jan 6th, 2015 8:23AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Persistent Slabs.

triley, Avalanche Canada

Purcells.

High avalanche danger is expected to continue for another day due to new storm slabs, high freezing levels, and above freezing air trapped in the alpine.

Summary

Confidence

Poor - Freezing levels are uncertain

Weather Forecast

Expect a lot of variability in this region due to the warm air from the West-Northwest meeting the cold arctic air from the Rockies. The West and South should be very warm with moderate Westerly winds, and the North and East should stay cooler with light Northeast winds. Freezing levels will vary on Wednesday as the storm ends and warm air tries to push East. Mostly clear on Thursday with cooler (alpine temperatures around -10) and drier conditions. Friday mostly clear with light winds and no precipitation.

Avalanche Summary

Natural and skier triggered avalanches up to size 2.0 releasing down 30-50 cm in the new storm slab.

Snowpack Summary

There is a great deal of variability across the region. The West and South have received up to 60 cm of storm snow in the past 48 hours, quickly followed by high freezing levels and warm air up into the alpine. The North and East of the region have had 20-30 cm of cold dry new snow over the past 48 hours with light Northeast winds. This new slab may be sitting on a patchy layer of surface hoar that was buried near the end of December. Deeper in the snowpack there is a persistent weak layer of surface hoar and crust that is now down about 60 cm.

Problems

Storm Slabs

The new storm slab is expected to continue to release naturally or be very easy to trigger with light additional loads like a skier or rider.

Give cornices a wide berth when travelling on or below ridges.>Travel on ridgetops to avoid wind slabs on slopes below.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

The new storm slab will add to the load above the mid-December persistent weak layer. This may not be enough load to trigger naturally, but may increase propagation distance and the likelihood of remote triggering.

Stick to small features with limited consequence and be aware of what is above you at all times.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Valid until: Jan 7th, 2015 2:00PM