Avalanche Forecast

Issued: Feb 17th, 2014 8:10AM

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

Avalanche Canada rbuhler, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The next Pacific frontal system will cross the South Coast on Tuesday resulting in strong wind and precipitation. Generally unsettled conditions are expected for Wednesday before another weak system affects the region Wednesday night or Thursday morning.Tuesday: Snowfall 20-30cm, afternoon freezing levels around 900m, ridgetop winds 40-60km/h SWWednesday: Cloudy with periods of sun, light intermittent snowfall 2-4cm, afternoon freezing levels around 700m, ridgetop winds 20-30km/h WThursday: Snowfall 5-15cm (might be Wednesday overnight), afternoon freezing levels around 700m, ridgetop winds 30-40km/h W-NW increasing in the afternoon

Avalanche Summary

On Sunday, numerous natural and human triggered slab avalanches up to size 3 were reported throughout the region. These were storm slab avalanches and occurred on all aspects and all elevation bands. 

Snowpack Summary

Total storm snowfall amounts exceed over 1.5m during the past week and has settled into a storm slab with a typical thickness of 60-100cm. This storm slab is overlying a variety of old weak surfaces that developed during the past dry spell. They consist of weak facets, surface hoar, a scoured crust, wind press, or any combination of these. A poor bond exists to these old surfaces.Particularly of concern is the combination of buried facets on a crust being unusually reactive at treeline and below. Avalanche activity, whumpfing and snowpack testing at these elevations are showing easy sudden planar results on the facet/crust combo. Strong to extreme winds are shifting the new snow into deeper, and destructive wind slabs on lee slopes.The mid and lower snowpack are generally strong and well-settled. Basal facets and depth hoar are likely to exist in some parts of the region, but triggering has become unlikely.

Problems

Storm Slabs

An icon showing Storm Slabs
An abundance of new snow has built a very touchy storm slab that is reactive at all elevation bands. The poor bond on a variety of old weak interfaces creates the perfect recipe for dangerous avalanche conditions. Thick wind slabs exist on lee slopes
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Stick to simple terrain and be aware of what is above you at all times.>Use caution in lee areas in the alpine and treeline. Recent wind loading have created wind slabs.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 5

Valid until: Feb 18th, 2014 2:00PM