Avalanche Forecast

Issued: Dec 28th, 2013 7:38AM

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

Avalanche Canada Peter, Avalanche Canada

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Tonight and Sunday: Mainly cloudy with light snow – 5-10 cm. The freezing level is around 1000 m but there is a chance of an above freezing layer near 1500 m. Winds are moderate to strong from the W-SW. Monday: Periods of snow – around 10 cm. The freezing level is near 1000 m and winds are moderate from the SW. Tuesday: Mainly cloudy with a chance of flurries and sunny breaks late in the day. The freezing level is near valley bottom.

Avalanche Summary

No new avalanches have been reported, but observations from the region are very limited. Areas with heavier recent snowfall likely experienced a natural avalanche cycle on Thursday/Friday. Rider triggering remains a concern in steeper terrain and wind loaded features, primarily at and above treeline.

Snowpack Summary

Recent storm snow totals in the region are around 40-50 cm, with moist or wet snow below treeline. Periods of moderate to strong W-SW winds were likely over the past couple days. Expect dense wind slabs in exposed lee terrain and cross-loaded features. Between 40 and 80 cm of snow sits on a crust that extends up to treeline and possibly beyond. This interface was "popping" under easy loads in snowpack tests a few days ago. A new surface rain crust will probably form at lower elevations as temperatures cool tonight. Deeper in the snow pack a layer of facets/surface hoar formed in early December can be found in the top 100cm in the Ashman. The mid and lower snowpack is still structurally weak and faceted. Depth hoar and an early season crust exist near the ground.

Problems

Wind Slabs

An icon showing Wind Slabs
New touchy wind slabs may develop with forecast snowfall and strong mountaintop winds over the next couple days.
Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
There is not much news on the buried mid-December rain crust. Watch for clues of instability and be prepared to dig and investigate if you plan on venturing into more committing terrain.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 29th, 2013 2:00PM

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