Avalanche Forecast

Issued: Feb 18th, 2015 7:36AM

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

Avalanche Canada Peter, Avalanche Canada

The snow is best up high, but this is also where lingering avalanche concerns exist. Please become a member of Avalanche Canada today at avalanche.ca/membership.

Summary

Confidence

Good

Weather Forecast

The ridge of high pressure flattens on Thursday allowing a couple weak disturbances to cross the province. We should see more cloud with possible light flurries each day. The freezing level is around 1400-1500 m on Thursday and should lower to around 800-1000 m by Saturday. Winds are light gusting moderate from the W-NW. The ridge rebuilds on Friday but we might not see full clearing until late Saturday. After this it looks like at least a few more days of dry and sunny weather.  

Avalanche Summary

On Tuesday a couple natural cornice falls were observed. These were size 2-2.5 but did not trigger slabs on the slopes below. There was also one report of a size 3 slab on a sun-exposed alpine slope. This slide was observed from a distance but did look fresh. Neighboring regions reported similar activity with cornice fall and isolated deep slabs being the main concern.

Snowpack Summary

The snow surface is a mix of surface hoar, crusts, 10-25 cm of low density snow, or wind affected snow depending on aspect and elevation. The "Valentine's Day" crust is just below the surface and is now strong and thick in most places. At alpine elevations, new wind slabs may have formed from NW winds, and cornices are large and weak. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) continue to give variable results in snowpack tests. Chances of triggering these weaknesses have decreased, but triggering may be possible from thin or rocky snowpack areas; or perhaps with a cornice fall, or an avalanche stepping down, especially on sun drenched slopes.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs may be lurking behind ridges and terrain features. Cornices are also large and weak and could collapse.
Be cautious as you transition into wind affected terrain.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Persistent slabs are most likely to be triggered from thin snowpack areas, or with large triggers like cornice fall or an avalanche stepping down.
Avoid common trigger spots, including convexities or areas with a thin or variable snowpack.>Avoid steep slopes below cornices.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Feb 19th, 2015 2:00PM

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