Avalanche Forecast

Issued: Jan 20th, 2018 4:40PM

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

Avalanche Canada jmcbride, Avalanche Canada

A storm system is expected to bring more snow and wind Saturday night and Sunday. Monitor how the new snow is bonding, avoid freshly wind-loaded areas and stay clear of overhead hazard.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

TONIGHT: Snow. Accumulation 10-15. Ridge wind strong, south. Temperature -5. Freezing level 800 m.SUNDAY: Snow. Accumulation 15-25 cm. Ridge wind strong, south. Temperature -3. Freezing level 1200 m.MONDAY: Flurries. Accumulation 5-10 cm. Ridge wind moderate, southwest. Temperature -5. Freezing level 1000 m.TUESDAY: Mostly cloudy, flurries. Accumulation 2-5cm. Ridge wind light, southeast. Temperature -5. Freezing level 800 m.

Avalanche Summary

Friday there were reports of natural and skier triggered avalanches (size 1-1.5) on west and northerly aspects above 1700 m failing both within the recent storm snow and up to 75 cm deep on the most recent mid-January crust.On Thursday several large (size 2-2.5) natural storm slab avalanches were observed on northerly aspects from 1200-2300 m, as well as one size 3 that was about 70 cm deep and propagated 250 m wide.Wednesday several natural and skier triggered avalanches from size 1 to 1.5 where reported at treeline and alpine elevations. Most of these were failing on the recent January 15th crust however one ski cut result was believe to have failed on the January 6th crust at 1950 m on a north aspect.

Snowpack Summary

Approximately 40-60 cm of storm snow lies above the most recent crust that was buried mid-January. This crust exists on almost all aspects and elevations with the exception of northerly aspects above 1850 m and has produced moderate to hard, sudden results in recent snowpack tests.Below this crust, a second thin crust that was buried early-January now lies 70-100 cm below the surface and has also been reactive in snowpack tests.Beneath this crust the mid and lower snowpack layers including the mid-December and late-November crust layers continue to produce hard, sudden results in snowpack tests in the northern part of the region and may still be a concern for step-down potential.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm snow and strong winds will continue to build storm slabs, particulary on lee slopes at upper treeline and alpine elevations. In northern parts of the region it may still be possible for a surface release to step down to a deeper layer.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Minimize overhead exposure during periods of heavy loading from new snow, wind.Avoid lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 3

Valid until: Jan 21st, 2018 2:00PM