Avalanche Forecast

Issued: Nov 29th, 2015 8:24AM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Loose Wet and Wind Slabs.

jlammers, Avalanche Canada

Kootenay Boundary.

Continued warming on Monday may increase the Avalanche Danger, especially at higher elevations.If you are out in the mountains, please share your observations on the MIN

Summary

Weather Forecast

Expect clear skies and valley cloud on Monday as the dry ridge of high pressure holds on for one more day. A strong inversion is forecast to deliver alpine temperatures of about 5' celsius. Below 1800m, temperatures should remain well below freezing. Monday's ridgetop winds should remain light from the northeast. The ridge should start to break down on Tuesday with increased cloud developing throughout the day. By Wednesday we may see trace amounts of new snow. Ridgetop winds are expected to be moderate from the southwest on Tuesday, and then strong and southwesterly on Wednesday. Freezing levels should hover around valley bottom for both days.

Avalanche Summary

No new avalanches have been reported. This may speak to the lack of observations rather than actual conditions. Given the combination of solar radiation and warm temperatures at higher elevations, there may have been a round of loose wet avalanche activity on steep, sun-exposed slopes.

Snowpack Summary

At treeline elevations, the snowpack appears to typically be 1-1.5m deep. Current snow surfaces likely include a mix of stubborn wind slabs in exposed higher elevation terrain, loose faceted snow and surface hoar in sheltered areas, and (depending on the time of day) moist snow or a re-frozen crust on steep solar aspects. In some parts of the region a thick hard crust is reported to exist between 15 and 25cm below the surface. For the time being, this hard crust is likely adding significant strength to the snowpack. That said, the combination of facets and surface hoar overlying a hard crust could become a reactive weak layer if it ever gets buried by new snow. There is also a thick crust from early-November in the middle of the snowpack. The limited reports we have received suggest that this crust is well bonded but you should investigate the snowpack in your local area before committing yourself to avalanche terrain. In general, there is a lot of uncertainty regarding snowpack structure throughout the region. If you have any observations to share, please submit them to our Mountain Information Network.

Problems

Loose Wet

Unseasonably warm temperatures and sun will increase the chances of loose wet avalanche activity on steep, sun-exposed slopes in the alpine and at treeline. Watch for conditions that change with aspect, elevation and time of day.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: North.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

Continued warm temperatures should help decrease the reactivity of recently formed wind slabs. Watch for triggering in steep, unsupported terrain, especially in spots where a hard underlying crust exists.

If you are increasing your exposure to avalanche terrain, do it gradually as you gather information. >Be cautious as you transition into wind affected terrain. >

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Nov 30th, 2015 2:00PM