Avalanche Forecast

Issued: Jan 17th, 2018 4:36PM

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

jmcbride, Avalanche Canada

South Coast Inland.

A wet and wild winter storm system with heavy snow, strong winds and mild temperatures is increasing the avalanche hazard. Travel in avalanche terrain is not recommend until the new snow has had a chance to settle and bond to the old surface.

Summary

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

TONIGHT: Snow. Accumulation 15-25 cm. Ridge wind extreme, southwest. Temperature near 0. Freezing level lowering to 1300 m.THURSDAY: Snow. Accumulation 10-20 cm. Ridge wind strong, southwest. Temperature -2. Freezing level 1300 m.FRIDAY: Cloudy, flurries. Accumulation 2-8 cm. Ridge wind moderate, southwest. Temperature -2. Freezing level 1000 m.SATURDAY: Cloudy, flurries. Accumulation 5-10 cm. Ridge wind moderate southwest. Temperature -2. Freezing level 1000 m.

Avalanche Summary

Reports from Tuesday indicate that the new snow had formed thin wind slabs that were reactive to skier triggers but had little mass or consequence. Expect this to change as new snow amounts accumulate with the approaching storm.On Sunday there was a report of a skier triggered size 2.5 slab avalanche in the northern part of the region that initiated as a 30 cm thick wind slab then stepped down to approximately 70 cm thick (likely the mid December layer) on a north-east aspect at 2050 m.

Snowpack Summary

A new snow (up to 25 cm in the northern areas and about 5 cm in southern parts) has buried the most recent, January 15th crust. This crust exists on almost all aspects and elevations with the exception of northerly aspects above 1850 m where the snow surface remained dry during the alpine inversion event on the weekend.Below the January 15th crust about 30-50 cm of snow overlies a 1 cm thick crust that was buried on January 6th which exists up to about 2000m. Mid and lower snowpack layers including the mid December and late November crust layers have produced moderate to hard, sudden results in snowpack tests in the northern part of the region last week and may be a concern for step-down potential.

Problems

Storm Slabs

New snow and strong winds will build touchy storm slabs particulary 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.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Minimize exposure during periods of heavy loading from new snow and wind or rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Loose Wet

It may be possible to trigger a loose wet slide in steep, unsupported or convex terrain where rain has soaked the upper snowpack.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Use extra caution on solar slopes or if the snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 18th, 2018 2:00PM