Avalanche Forecast

Issued: Feb 14th, 2015 7:41AM

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

Avalanche Canada pgoddard, Avalanche Canada

Enjoy any sun that comes out, but be aware of its effect on the snowpack avoid exposure to sun-affected slopes. They may be far above you.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Flurries taper out on Sunday. Freezing level is around 1400 m on Sunday, falling to valley floor overnight as a strong ridge sets up. It’s expected to get into a diurnal cycle after that (falling to valley floor at night and rising by day to around 1200 m). Monday and Tuesday are dry and cool, with a chance of sun. Winds are moderate NW, easing to light by late Sunday.

Avalanche Summary

Several size 1.5-2.5 avalanches were triggered naturally on Thursday and Friday in response to storm loading, wind and warm temperatures. A number of cornice collapses have been reported over the last few days. Loose wet avalanches failed naturally in steep terrain on Wednesday in response to warming. Also on Wednesday, explosives triggered a couple of size 2 slabs, which failed on the late-Jan crust. Human-triggering of the persistent slab remains possible.

Snowpack Summary

New snow may have been shifted into wind slabs on lee features at alpine and treeline elevations. Keep your eyes open for cornices, which may be large and unstable. A week or so of very warm temperatures has affected the snowpack, creating moist surface layers up to around 2000m. At low elevations, the snowpack may now be relatively uniform and starting to refreeze. The late-Jan crust/surface hoar layer, buried around a metre deep, remains a key concern, as it could still be human-triggered and could produce a destructive avalanche. The mid-January surface hoar is typically down 80-120cm and is unlikely to be triggered, apart from in a thin or rocky snowpack area. The mid-December weak layer is down over 120cm, but has been generally unreactive lately. Basal weaknesses remain in the back of operators' minds.

Problems

Persistent Slabs

An icon showing Persistent Slabs
A buried crust formed in late January has acted as a sliding surface for large avalanches. A cornice fall or small avalanche could also step down to a more deeply buried persistent weak layer.
Avoid steep slopes below cornices.>Avoid common trigger spots, including convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Storm Slabs

An icon showing Storm Slabs
At low elevations or on sun-affected slopes, loose wet avalanches remain possible, especially on steep terrain. Recent snow and wind may have created storm slabs and wind slabs.
Choose well supported terrain without convexities.>Be cautious as you transition into wind affected terrain.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Feb 15th, 2015 2:00PM