Avalanche Forecast

Issued: Feb 7th, 2019 5:02PM

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

Avalanche Canada cgarritty, Avalanche Canada

Areas closer to the coast have a bit of new snow available for outflow winds to build slabs with on Friday. Further inland, wind slabs of concern are likely limited to more extreme terrain in the alpine.

Summary

Confidence

Moderate -

Weather Forecast

Thursday night: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate north winds.Friday: Cloudy with clear periods. Moderate to strong northeast winds, increasing overnight. Alpine high temperatures around -10 and falling over the day.Saturday: Sunny. Moderate to strong northeast winds easing over the day. Alpine high temperatures around -11.Sunday: Sunny. Strong to extreme northeast winds easing over the day. Alpine high temperatures around -15.

Avalanche Summary

Reports from Wednesday showed explosives control yielding mainly small (size 1) wind slab releases in the Shames area. Several other recent small (size 1.5) natural wind slab releases were observed in alpine features in the Legate Peak area.Tuesday's reports showed more limited wind slab reactivity, with one smaller (size 1.5) wind slab triggered with a ski cut.Reports from Monday included several small (size 1.5) remote triggered (triggered by a skier at a distance) wind slabs on north aspects at around 1500 metres. Slab depths were 20-25 cm and they had failed on the crust buried beneath our recent storm snow.

Snowpack Summary

Light new snow amounts fell over the region on Wednesday night, mainly in coastal areas. This buried surface snow that has been faceting (becoming sugary) under the influence of recent cold temperatures. The uppermost layer of the snowpack is composed of a heavily wind-redistributed 40 cm of storm snow from the weekend. Some older wind slabs may still linger in steeper lee and cross-loaded terrain features, but these are a diminishing concern as cold temperatures work to decrease their cohesion and reactivity.Collectively, this wind-affected and faceting storm snow overlies previously wind-affected surfaces in the high alpine and a thick melt-freeze crust at and below treeline.In the south of the region, the remainder of the snowpack is well-settled.Around Bear Pass and in the north of the region, there is a weak layer of feathery surface hoar crystals about 50 cm deep. This weak layer is likely most prominent in sheltered and shaded areas. Also in the north, a few weak layers may still exist within the middle and lower half of the snowpack. These include another layer of surface hoar around 70 to 100 cm deep and a weak layer of sugary faceted snow around 200 cm deep.

Problems

Wind Slabs

An icon showing Wind Slabs
Forecast outflow winds from the northeast are expected to transport loose surface snow into thin new wind slabs on lee aspects on Friday.
Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Analyze slopes for patterns of wind loading as you transition into wind affected terrain.

Aspects: South East, South, South West, West, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Valid until: Feb 8th, 2019 2:00PM

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