Avalanche Forecast

Issued: Jan 10th, 2019 4:05PM

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

dsaly, Avalanche Canada

Kootenay Boundary.

Recent snow and wind have developed slabs. The deepest and most reactive deposits of snow will be found in wind-loaded terrain.

Summary

Confidence

Low - Freezing levels are uncertain

Weather Forecast

THURSDAY NIGHT: Cloudy with scattered flurries, trace to 5 cm snow. Light south-southwest wind. Freezing level 1400 m.FRIDAY: Mostly cloudy, no precipitation. Light south-southwest wind. Freezing level 1500 m.SATURDAY: Cloudy with sunny periods. Light south wind. Freezing level rising above 2000 m, chance of inversion.SUNDAY: Mix of sun and cloud. Light southwest wind. Freezing level 1800 m, chance of inversion.More details can be found in the Mountain Weather Forecast.

Avalanche Summary

On Thursday, explosives triggered storm slab avalanches to size 2. Around the region, up to 25 cm new storm snow was reacting to skier traffic. Near Red Mountain a backcountry skier was caught in a avalanche, a storm slab is suspected to have been triggered.On Wednesday, natural avalanches to size 2 were reported around the Whitewater area. Through the day, explosives triggered storm slab avalanches to size 2 and ski cuts triggered storm slab avalanches to size 1.5. Several small wind slabs were triggered by people on Monday on north to north-east aspects near treeline. On Sunday, several explosives-triggered avalanches to size 2 were reported in the region at or near treeline on all aspects.

Snowpack Summary

Around 20-40 cm recent snow around the region falling with moderate to strong winds and increasing temperatures have created variable storm slabs and wind slabs. Approximately 60 cm snow has accumulated since Dec 31. Wind slabs were observed at all elevations on Monday and may be hidden under the most recent snowfall. Isolated layers of surface hoar and or crusts may be found in the upper snowpack. A weak layer buried early December is down 60-120 cm in the alpine and treeline elevations. It consists of a rain crust, surface hoar, and facets (sugary snow). Professionals are continuing to monitor this interface and although the likelihood of triggering has gone down, if triggered this weak layer has the potential to produce large avalanches. This layer is most likely to be triggered from thin, rocky areas with a variable snowpack or with a large load, like cornice fall.

Problems

Storm Slabs

Storm slabs have developed with recent snow and southerly winds. Deeper and more sensitive deposits of snow will be found in wind-loaded terrain: under cornices and roll-overs, cross-loaded areas, and lee terrain features.

Look for signs of instability such as whumpfs, hollow sounds, shooting cracks or recent avalanches.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Wet

Rising freezing levels are forecasted. The chance for loose, wet avalanches will increase as the snowpack warms.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Jan 11th, 2019 2:00PM