Avalanche Forecast

Issued: Mar 10th, 2014 10:01AM

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

Avalanche Canada bcorrigan, Avalanche Canada

Warming temperatures and Solar radiation will play a leading role in the avalanche hazard in the coming days. Pay special attention to large ripe cornices !

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Synopsis: The Pineapple express that plowed its way across the province in the last few days has moved south and east leaving us with a high pressure ridge for the next few days.Tonight: Cloudy with light to locally moderate precipitation, freezing level should drop to valley bottom. ridge top winds light to moderate from the north west.Tuesday: Mix of sun and clouds, no precipitation in the forecast, light to moderate winds at ridge tops, freezing level climbs to 1500m, and possibly above.Wednesday: Sunny with cloudy periods, no precipitation in the forecast, freezing level rising to 1800m. winds from the south west, light to moderate.Thursday:  Sunny with cloudy periods, possibility of flurries, freezing level rising to 1800m. Light ridge top winds.

Avalanche Summary

There was a report that the Morrisey slidepaths near Fernie ran to nearly full path on Sunday. Also on Sunday, near neighbors in the Lizard Range report storm slabs and loose wet avalanches to size 2.5.There is concern for an ongoing natural and human triggered avalanche cycle on Monday with more snow in the south, and solar radiation hitting the slopes when we get some blue skies. Cornices have gotten large and tender and may trigger slabs if they fail.Avalanches in the region have the potential to run full path as dryer storm slabs from the alpine entrain moist snow as they descend. Avalanches in clearcuts, road banks, lower angle terrain and non obvious avalanche paths continue to surprise backcountry enthusiasts throughout the region, so consider them carefully in your travel plans through the forecast period.

Snowpack Summary

Storm slabs continue to build on top of the March 2nd weak layer which consists of facets, surface hoar and/or crusts, depending on your elevation and aspect. There is now 70-100cm of snow on this layer in the deeper snow-pack zones in the south of our region (Flathead and around Fernie).The mid pack contains the February 10th persistent weak layer, which in some of the deeper snowpack regions, could be up to 2 meters deep. In the shallower snow packs it is likely about a meter deep, and is becoming a more isolated problem, and probably could only be triggered by a large load, a cornice failure or storm a slab in motion.  Be aware of slopes that have not yet not run on the February 10th layer... but those areas are getting harder to find.In the lower elevations (below 1600m) in the south of the region, expect the snowpack to be rain soaked and loosing cohesion. Below tree line the snow pack is most likely close to isothermal in rain affected areas, and at least moist everywhere else.

Problems

Storm Slabs

An icon showing Storm Slabs
Rising freezing levels and solar radiation for the first time since the last storm may trigger storm slabs or cornice failures. New snow and continued warm temperatures will add to the storm slab problem in the south of the region.
The new snow will require several days to settle and stabilize.>Avoid freshly wind loaded features.>Caution required around loaded road banks, cutblocks and other non obvious avalanche terrain>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Wet Slabs

An icon showing Wet Slabs
Wet slabs are a concern on slopes with rain soaked snow now sitting over weak layers. Wet loose avalanches are also expected where rain soaked snow has lost its cohesion. Warm temperatures and solar radiation will contribute to the hazard.
Avoid steep unsupported terrain below treeline especially if the snow is moist or wet.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Use conservative route selection, resist venturing out into complex terrain even if you observe no obvious signs of unstable snow.>Consider the consequences of the terrain if an avalanche steps down to a persistent weakness.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 11th, 2014 2:00PM