Avalanche Forecast

Issued: Dec 25th, 2015 7:46AM

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

ghelgeson, Avalanche Canada

South Rockies.

Storm slabs have remained sensitive to human triggering longer than expected. Exercise due diligence and carefully investigate the new/old snow interface before committing to your line.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

A major storm will impact the Northwest Coast on Saturday, the scraps of that system may bring isolated convective flurries to the South Rockies on Monday. SATURDAY: No significant snowfall expected, freezing level at valley bottom, moderate winds, generally out of the west. SUNDAY: No significant snowfall expected, freezing level at valley bottom, strong winds out of the west. MONDAY: Isolated convective flurries but no significant accumulations expected, freezing level at valley bottom, light variable winds.

Avalanche Summary

On Thursday control work produced numerous small loose snow avalanches within the recent storm snow. On Wednesday we received a report of a skier triggered size 1 wind slab on a north aspect at 1800m. It's thought that this avalanche failed on the December 9th melt freeze crust which was down 40cm at the location of the avalanche.

Snowpack Summary

The series of recent storms has left us with around 50 to 80cm of new snow. Previously strong to extreme SW winds created wind slabs at all elevations. These have now been buried by subsequent snowfall, making them hard to spot. Cornices exist on many ridge crests. Storm snow from the last week overlies a hard rain crust. This strong, thick crust seems to be effectively isolating the lower snowpack.

Problems

Storm Slabs

Storm and wind slabs from 15 to 50cm in depth may still be sensitive to human triggering Saturday. The usual problem areas like convexities, steep unsupported terrain features and the more complex lines should probably be avoided at this time.

Give cornices a wide berth when travelling on or below ridges.>Choose well supported terrain without convexities.>Avoid recently wind loaded features and use ridges/ribs to sneak around these problem areas.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Dec 26th, 2015 2:00PM