Avalanche Forecast

Issued: Jan 22nd, 2014 8:43AM

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

ccampbell, Avalanche Canada

Sea To Sky.

Summary

Confidence

Good

Weather Forecast

Thursday: A mix of sun and cloud. Freezing levels nearing 2000m with moderate westerly winds. Friday and Saturday: A mix of sun and cloud with light winds and freezing levels over 3000 m. Temperature at 2000m could reach as high as +10 C, but valley bottoms could be slightly cooler.

Avalanche Summary

No new avalanches were reported on Tuesday.

Snowpack Summary

Unseasonably warm daytime temperatures and sun-exposure have subjected the snow surface to melt-freeze cycles on all but high elevation shady aspects for several days. Cornices have also been weakening. Previous winds have scoured windward slopes and sculpted sastrugi in exposed areas. Average treeline snowpack depths are around 170 cm with a well settled and strong upper and mid-pack; however, facets and depth hoar with an associated crust still lurk near the base. Recent snowpack tests on a SSW facing treeline slope gave hard but sudden results on a crust laminated with facets down 118cm. Below that, facets and depth hoar were found down to the ground.

Problems

Deep Persistent Slabs

Particularly a concern on shallow rocky southern aspects with heavy triggers. Warm temperatures and sun-exposure is expected to increase the likelihood of triggering these facets deep in the snowpack. Cornice falls could also act as natural triggers.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Use caution on rocky or sparsely-treed slopes.>Use caution around convexities or areas with a thin or variable snowpack.>Avoid exposure to sun exposed slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

4 - 7

Valid until: Jan 23rd, 2014 2:00PM