Avalanche Forecast

Issued: Dec 30th, 2013 9:07AM

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

ghelgeson, Avalanche Canada

South Rockies.

Summary

Confidence

Poor - Due to the quality of field observations

Weather Forecast

Synopsis: The Southeast corner of the province remains largely high & dry for the forecast period. There is potential for a bit of precip as a weakening system exits the province Thursday night.Tuesday: Freezing Level: Valley Bottom; Precip: Trace; Wind: Mod W/NW. Strong at ridgetop.Wednesday: Freezing Level: Valley Bottom; Precip: Trace; Wind: Light SWThursday: Freezing Level: Rising, perhaps as high as 2000m; Precip: Nil Wind: Strong SWThursday Night: Freezing Level slowly lowers overnight Precip: 3/7mm

Avalanche Summary

No significant avalanche observations have been reported.

Snowpack Summary

There appears to be a lot of snowpack variability across the region. Snowpack depths at treeline vary from 60 - 130 cm with high variability in wind-exposed areas. Winds were strong out of the SW on Sunday at all stations & our field team reports that alpine terrain has been heavily wind effected. In the mid pack is the late-November/early-December interface which is made up of surface hoar, a crust, and/or facets. This layer is typically down 30-70cm and has reached the tipping point for rider triggering in a few areas including the Harvey Pass area. Check out this video of a recent snowpack test on this layer.

Problems

Wind Slabs

With very little snow available for transport fresh wind slabs likely won't be much of an issue. Wind slab formed over the last few days may still be sensitive to rider triggering, especially on slopes immediately lee of ridgecrest.

Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>Avoid freshly wind loaded features.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

This is a complex problem because it's different from one drainage to the next. You need to dig down and figure out if you have a slab on top of the buried surface hoar. If you find a slab in your riding area a conservative approach is appropriate.

Make observations and assess conditions continually as you travel.>Dig down to find and test weak layers before committing to a line.>Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Dec 31st, 2013 2:00PM