Avalanche Forecast

Issued: Mar 2nd, 2014 8:10AM

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

Avalanche Canada rbuhler, Avalanche Canada

Summary

Confidence

Fair

Weather Forecast

Unsettled conditions are expected for the forecast period with light flurries and periods of sun. A more organized system is expected for late-Wednesday or Thursday.Monday: Cloudy with sunny breaks, flurries 1-4cm, freezing level rising to around 1200m, ridgetop wind 40-60 SWTuesday: Cloudy with sunny breaks, flurries 3-6cm, freezing level around 1300m, ridgetop wind 30-50 SWWednesday: Cloudy with sunny breaks, flurries 3-6cm, freezing level around 1400m, ridgetop wind 20-40 SW

Avalanche Summary

We have not received any reports of new avalanches since the solar triggered activity a few days ago. However, recent snowpack tests imply that where the layer still exists, the potential for large, destructive avalanches still exists.

Snowpack Summary

The primary concern remains a persistent slab that sits on a stubborn persistent weak layer consisting of a crust, facets, and/or surface hoar. The layer continues to show a high degree of sensitivity to human triggers. Wide propagations and remote triggering remain a concern. In the thinner snowpack areas such as the Crowsnest and northern Elk Valley, the slab is typically 30-60cm thick. In thicker areas such as the Flathead and around Fernie, the slab typically varies in thickness from 70-150cm. Check out the South Rockies Blog for a video discussing the persistent weak layer and the current avalanche problem. Outflow winds from the N-NE created reverse-loaded wind slabs a few days ago. More recent strong SW winds have created new, touchy wind slabs on the opposite aspects.  Cornices remain a concern along ridge lines and threaten the slopes below. South facing slopes have formed a sun crust on the snow surface. New surface hoar formation up to 4mm and near-surface faceting are also being reported. A weakness at the base of the snowpack may still exist in isolated areas of the region but triggering has become unlikely.  New snowfall is currently burying this layer.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Expect the buried persistent weak layer to continue to produce large and destructive avalanches. Many slopes are still primed for human triggering and remain a concern on all aspects and elevations.
Avoid unsupported slopes.>Remote triggering is a concern, watch out for adjacent slopes.>Use conservative route selection, resist venturing out into complex terrain even if you observe no obvious signs of unstable snow.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

3 - 6

Wind Slabs

An icon showing Wind Slabs
Recent strong winds from the north resulted in reverse loading.  Winds are now from the SW and forming new wind slabs.  Expect wind slabs on all aspects in wind affected terrain.
Be cautious as you transition into wind affected terrain.>Avoid freshly wind loaded features.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 3rd, 2014 2:00PM