Avalanche Forecast

Issued: Jan 8th, 2015 8:31AM

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

ccampbell, Avalanche Canada

Purcells.

Diligence may be required to maintain conservative decisions in the face of fair weather and decent riding conditions over the weekend.

Summary

Confidence

Good

Weather Forecast

Mostly cloudy with a chance of light flurries Friday evening and Saturday, but generally dry for Sunday. Freezing levels remain in valley bottoms for the forecast period, with above freezing alpine temperatures expected for Friday. Winds should remain generally light and variable.

Avalanche Summary

Reports from Wednesday include several explosive triggered persistent slab avalanches up to Size 3, some running on facets near the ground. Numerous natural 40-60 cm thick slab avalanches up to Size 2 were also observed south through west facing treeline and alpine slopes in response to sun-exposure.

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 earlier in the week, 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 with light Northeast winds. This new slab may be bonding poorly to 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

15-30 cm of recent storm snow is settling into a cohesive soft slab that is highly sensitive to human triggers.

The new snow will require several days to settle and stabilize.>Give cornices a wide berth when travelling on or below ridges.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

A persistent weakness buried mid-December is primed for human triggers in specific areas. Watch for signs of instability especially during daytime warming.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Jan 9th, 2015 2:00PM