Avalanche Forecast

Issued: Dec 24th, 2015 8:51AM

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.

As storm and wind slabs become less sensitive to rider triggering, it becomes more important to exercise due diligence and carefully investigate the new/old snow interface before committing to the more challenging lines.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

After a very active pattern that has delivered storm after storm, the pendulum is swinging to the opposite end of the spectrum. Wind is the big story for the forecast period, but we are not expecting any new snow in the South Rockies until at least the New Year. CHRISTMAS: No snow expected, freezing level at valley bottom, light N/NW winds. BOXING DAY: No new snow, freezing level at valley bottom, light W/SW winds. SUNDAY: No significant precipitation, freezing level at valley bottom, moderate SW winds at treeline, strong to extreme SW winds at ridgetop.

Avalanche Summary

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 50-80 cm new snow. Strong to extreme SW winds in specific areas in the south of the region on Sunday created wind slabs at all elevations. These may now be buried by subsequent snowfall, making them hard to spot. Cornices exist on many ridge crests. Recent storm snow 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 10 to 40cm in depth may still be sensitive to human triggering Friday. The usual problem areas like convexities, steep unsupported terrain features and the more complex lines should probably be avoided at this time.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Dec 25th, 2015 2:00PM