Avalanche Forecast

Issued: Jan 21st, 2017 3:59PM

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

Avalanche Canada mgrist, Avalanche Canada

Conditions are primed for people triggering avalanches. Don't let the lure of deep powder draw you into terrain that's inappropriate for the conditions.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Unsettled weather and seasonal temperatures for Sunday; a mix of sun and cloud for early next week. SUNDAY: Mainly cloudy with isolated flurries, local accumulations 5-10cm near Whistler with more possible in southern areas. Moderate southeasterly wind and freezing level around 1200m. MONDAY: Sunny with cloudy periods, light northerly wind and freezing level around 1100m. TUESDAY: Sunny with cloudy periods, light northwesterly wind and freezing level around 1200m.

Avalanche Summary

We are still receiving reports of skier (accidental) triggered Size 1 to 1.5 avalanches in the recent storm snow at treeline and higher. Cornices have also been touchy at ridge crests.  Avalanche control work with explosives resulted in storm slab and cornice releases to Size 2.5.

Snowpack Summary

Rapid snow and wind loading occurred during the week. The storm snow fell in fluctuating freezing levels, creating storm snow weaknesses. By Friday morning another 15 cm of new snow brought storm snow totals to 70-140cm, which has been redistributed by southerly winds. Early last week we had rain up to 2200m near Whistler, while in other zones like the upper Callaghan it was 35 cm or more of fresh snow. The rain (or snow high in the alpine) started to saturate and load a wide variety of previous surface conditions. Simply put, the upper snowpack is extremely variable with weaknesses within and under the recent storm snow. Of most recent concern is touchy pockets of wind slab that developed Friday on northwesterly features above 2000m.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow is bonding poorly to the previous snow surface. Expect avalanche likelihood and size to increase with increased snow and wind-loading. Slabs will be particulary deep and touchy on wind-loaded northerly aspects near ridge crests.
The new snow will require several days to settle and stabilize.Use caution in lee areas. New snowfall mixed with wind loading is creating Wind Slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Wind Slabs

An icon showing Wind Slabs
Watch out for touchy pockets of wind slabs on exposed north through easterly features near ridge crests, and cross-loaded southeasterly gullies at treeline.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Jan 22nd, 2017 2:00PM

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