Avalanche Forecast

Issued: Nov 28th, 2013 8:47AM

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

jfloyer, Avalanche Canada

Cariboos.

Heads up this weekend for a significant storm, bringing new snow, high winds and elevated avalanche danger.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

A significant storm is approaching this region for the weekend. Expect snow and high winds.Friday: Flurries, turning to light precipitation at the end of the day. Strong westerly ridgetop winds. Freezing level around 800 m.Saturday:10-15 cm new snow. Strong westerly winds continue. Freezing level around 800 m.Sunday: 10-25 cm new snow. Some areas may see significant snowfall rates. Strong SW winds. Freezing level lowering to surface.

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

Light snow has buried surface hoar that has grown this week, which is likely most prevalent on shady slopes at upper treeline and lower alpine elevations. On southern aspects, a expect a thinly buried crust. Snowpack depths at treeline elevations are about a metre, with some wind loaded pockets reported to be near 2 metres deep. Below the recent new snow, the upper snowpack is fairly well settled. A buried surface hoar layer may exist around 60 cm down but seems to be spotty, and drainage specific. Deeper in the snowpack near the base is a melt-freeze / rain crust that formed in October. This is generally found from 80-160 cm down near the base of the snowpack. This layer was reported to be down about 90 cm and "a hard ice crust" on the West slope of the Caribous near Wells Gray Park. Snow pack depths are low for this time of year, with snow pillow data showing that most areas are below average and some are near minimum since data has been collected.

Problems

Persistent Slabs

The possibility of triggering an avalanche on a buried layer of surface hoar from mid-November (down around 60) is still there and this weak layer deserves our attention, especially as new snow starts to add load to the snowpack.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar and a buried crust.>If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Nov 29th, 2013 2:00PM