Avalanche Forecast

Issued: Jan 21st, 2017 4:02PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm 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 - Due to the number of field observations

Weather Forecast

Unsettled weather and seasonal temperatures for Sunday. A mix of sun and cloud for early next week. SUNDAY: Mainly cloudy with convective flurries bringing 3-8 cm, freezing levels around 1200m with moderate to strong southeasterly winds. MONDAY: A mix of sun and cloud. Freezing levels around 1100m with light northerly winds. TUESDAY: A mix of sun and cloud. Freezing levels around 700m with light northerly winds.

Avalanche Summary

We've had a widespread natural avalanche cycle this week, including a spooky Size 3 early Thursday morning that buried the Duffey Lake road 5 metres + deep. Avalanche control work in the northwest of the region gave several large avalanches sized 2.5 to 4, running full depth (1.5m crown) on the storm snow layer. Reports from Wednesday and Thursday included widespread natural slab avalanches up to Size 3 with crowns up to 80 cm thick. Lastly, below treeline areas up the Lillooet / Meager drainages have been touchy and danger is likely to remain higher in this zone.

Snowpack Summary

SOUTHERN AREAS (e.g. Coquihalla): 10-20cm of fresh snow is likely bonding well to the previous rain-soaked snow surface up to treeline elevations. At alpine elevations, up to 40cm of storm snow fell and touchy wind slabs are likely forming on northerly aspects. NORTHERN AREAS (e.g. Duffey Lake): Up to 45 cm of fresh snow by Friday morning brings the storm snow totals to over a metre, which was all redistributed by moderate to strong southerly winds. This has resulted in touchy storm and wind slabs bonding poorly to the previous snow surface that includes facets and large surface hoar on sheltered slopes and/or a sun crust on steep sun-exposed aspects, as well as wind-affected surfaces (e.g. hard wind slab, sastrugi, scoured crust, etc.) in exposed areas. Weaknesses within the recent storm snow have also been highly sensitive to triggering.

Problems

Storm Slabs

An icon showing Storm Slabs
Weaknesses exist within and under the new snow. Slabs will be particulary deep and touchy on wind-loaded northerly aspects near ridge crests. Small avalanches may "step down", resulting in large destructive avalanches.
The new snow will require several days to settle and stabilize.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

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

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