Avalanche Forecast

Issued: Jan 29th, 2013 9:45AM

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

Avalanche Canada swerner, Avalanche Canada

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Wednesday: High pressure moves into the region gradually pushing out the low. Light snowfall amounts accompanied by Westerly ridgetop winds near 45km/hr. Alpine temperatures near -6.0 and freezing levels around 600 m. Thursday: Upper trough embedded in the flow causing unsettled conditions. Snow amounts 5-10 cm accompanied by moderate ridgetop winds from the SW. Alpine temperatures near -5.0 and freezing levels rise to 900 m.Friday: Unsettled conditions continue. Snow amounts 10 cm with ridgetop winds light from the SW. Alpine temperatures -3.0 and freezing levels staying near 900 m.

Avalanche Summary

Natural avalanche activity occurred on higher elevation wind loaded slopes up to size 2.0. Loose snow avalanches were also reported running in the storm snow treeline and below elevations.

Snowpack Summary

The region has received close to a meter of recent storm snow. This new snow has been building storm and wind slabs over a variety of old snow surfaces (old wind slabs, melt-freeze crusts, surface hoar and scoured slopes). Much of the recent snow is being drifted into big wind slabs by strong NW wind.  Reports generally indicate that the bulk of this storm snow seems to be settling quickly, which is a good. However, with a continued stormy pattern I would wait out the storms and watch how the snowpack adapts  to the rapid changes.Lingering beneath the new snow sits two persistent weaknesses comprising of surface hoar/ facets and a melt-freeze crust. I suggest you keep these on your radar in regards to reactivity and sensitivity with the additional loading pattern. If reactive, with up to a meter of new snow regionally,  these buried weaknesses may be susceptible to producing large avalanches. The mid and lower snowpack is generally well settled and strong, although basal facets remain a concern in the northern part of the region.

Problems

Storm Slabs

An icon showing Storm Slabs
Recent storm snow has built storm slabs at all elevations. Strong shifting winds will build touchy wind slabs that are likely found behind terrain breaks such as ridges and ribs, especially in areas where the slab sits over a buried weak layer.
Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>The new snow may require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Jan 30th, 2013 2:00PM

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