Avalanche Forecast

Issued: Feb 14th, 2019 5:12PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs and Persistent Slabs.

Avalanche Canada mbender, Avalanche Canada

Forecast precipitation is uncertain on Friday. Areas south of Nakusp may receive more snow than is currently forecast. If amounts are locally higher than indicated, danger may be Considerable.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

THURSDAY Night: Mainly cloudy with isolated flurries, light to moderate southeast wind, alpine temperature -9 C.FRIDAY: Flurries, accumulation 5-15 cm , light to moderate southwest wind, alpine temperature -8 CSATURDAY: Flurries, accumulation 5-15 cm, light west wind, alpine temperature -9 CSUNDAY: Mix of sun and cloud, light northeast wind, alpine temperature -13 C

Avalanche Summary

Numerous size 1-2 windslab, storm slab and persistent slab avalanches were reported from areas in the south of the region on Tuesday and Wednesday. These were predominantly at treeline and in the alpine on all aspects. In the the north part of the region avalanche activity on Wednesday was primarily reported as windslabs to size size 1.5 on north, west and south aspects in the alpine and at treeline.

Snowpack Summary

Up to 25 cm of new snow fell in the southern portion of the region (south of Nakusp) Tuesday into Wednesday. 5-10 cm fell further north. This new snow is sitting on previously wind-affected surfaces, sugary facets or feathery surface hoar. Beneath this lies two weak layers of surface hoar, which have produced large avalanches in the region. A layer that was buried at the end of January is around 30 cm deep and a layer buried mid-January is between 40 and 90 cm deep. The mid-January layer may also be associated with a melt-freeze crust on southerly aspects. These layers are most prominent at treeline and below.The remainder of the snowpack is generally well-settled. However, there have been sporadic reports of very large avalanches that have released near the base of the snowpack. Most of the avalanches have been in the high alpine. There has been about one report a week for the past month.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent new snow falling with wind has formed new wind slabs in wind exposed features. Older buried windslabs may still be reactive.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Two weak layers of surface hoar crystals are buried between 30 and 90 cm in the snowpack. The layers are most prominent at treeline and below.
Avoid steep, open and/or sparsely treed slopes at and below treeline.Be aware of the potential for wide propagation.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Feb 15th, 2019 2:00PM