Avalanche Forecast

Issued: Dec 26th, 2013 7:45AM

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

Peter, Avalanche Canada

Northwest Inland.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Friday: Precipitation eases off in the morning, then cloudy with flurries. The freezing level lowers to around 800 m. Winds are light to moderate from the W-NW. Saturday: Mainly cloudy with a chance of flurries. The freezing level is near valley bottom and winds are light to moderate from the west-southwest. Sunday: Periods of snow 5-10 cm. The freezing level could climb to 1000 m.

Avalanche Summary

No new avalanches have been reported, but observations are very limited. Areas with heavier recent snowfall may have experienced a natural avalanche cycle. Rider triggering remains a concern in steeper terrain and wind loaded features.

Snowpack Summary

The region has received around 20-30 cm of snow over the past couple days. Moderate to strong W-SW winds were likely during the stormy periods, forming dense wind slabs in exposed lee terrain. Between 30 and 80 cm of snow sits on a crust that extends up to treeline and possibly beyond. This interface has been "popping" under easy loads in snowpack tests.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

Storm Slabs

Triggering is most likely on steeper north through east facing slopes at and above treeline where dense wind slabs are likely.

Be cautious as you transition into wind affected terrain.>The new snow will require several days to settle and stabilize.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

A couple of weak layers from earlier in the month are lurking in the top meter of the snow pack. Continued loading and settlement of the overlying snow may increase the likelihood of triggering an avalanche one of these layers.

Avoid convexities or areas with a thin or variable snowpack.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 27th, 2013 2:00PM