Avalanche Forecast

Issued: Feb 17th, 2016 9:03AM

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.

jlammers, Avalanche Canada

Kootenay Boundary.

You may be managing more than just the new snow. A reactive crust lies up to 70cm below the surface, and can produce surprisingly large avalanches.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

WEDNESDAY NIGHT: 5-10cm of snow / moderate southwest winds / freezing level at about 1800mTHURSDAY: 5-10cm of snow / moderate southwest winds / freezing level dropping from 1800m to 1500m throughout the dayFRIDAY: light snowfall with 10-15cm of new snow falling overnight / moderate southwest winds / freezing level at about 1200mSATURDAY: light flurries with a mix of sun and cloud / light northwest winds / freezing level at about 1000m

Avalanche Summary

Numerous size 1-2 natural, skier-controlled, and explosive controlled slab avalanches were reported on Monday and Tuesday. Some of these slabs failed on the buried crust mentioned in the Snowpack Discussion. These slabs were reported on all aspects, and were mainly on slopes above 1800-1900 m.Â Below 1800 m there have been ongoing reports of size 1-1.5 loose wet sluffs on steeper terrain.

Snowpack Summary

On Thursday expect new wind slabs to develop at treeline and in the alpine. Rain at lower elevations will continue to saturate the upper snowpack. 35-70 cm of recent storm snow sits on a supportive crust at and below treeline, a breakable crust on south-facing slopes in the alpine, buried surface hoar in sheltered terrain, or old wind affected surfaces.Â A few buried surface hoar layers exist in the top 100 cm in drier areas on the west side of the region. In other areas the notable early January surface hoar layer is 80-130 cm deep and poses a low probability/ high consequence threat. It should remain on your radar, especially in thin snowpack areas and during periods of significant warming or rapid loading.

Problems

Storm Slabs

New snow and wind on Wednesday night and Thursday will form new wind slabs in lee terrain and add to a developing storm slab. Storm slab avalanches may be surprisingly large if they fail on a buried crust located up to 70cm below the surface.

Use ridges or ribs to avoid pockets of wind loaded snow.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Loose Wet

Rain at lower elevations will encourage loose wet avalanche activity in steep terrain. Loose wet avalanches can be pushy and entrain mass quickly.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 18th, 2016 2:00PM