Avalanche Forecast

Issued: Jan 10th, 2016 7:27AM

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

pgoddard, Avalanche Canada

Purcells.

Some snow in the forecast this week. Check back for updates as the storm progresses.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Dry conditions persist on Monday, before a Pacific system brings light snow on Tuesday and Wednesday. Tues: 2-5 cm, Wed: 5-10 cm. Winds are expected to be moderate from the SW and the freezing level remains at valley floor. For more details check out http://www.avalanche.ca/weather.

Avalanche Summary

A cycle of naturally-triggered size 1-2 loose dry avalanches was reported on Friday. Most were on steep alpine shady aspects.

Snowpack Summary

Conditions are variable across the Purcells. Isolated wind slabs may be lurking behind ridges and ribs. Wind slabs or loose dry snow overlie old surfaces including surface hoar, near surface facets, and possible sun crusts on steep southerly aspects. Cold and dry weather is drying out the upper snowpack (through faceting). In parts of the Purcells, two prominent layers of surface hoar are reactive in snowpack tests. These are buried down 25-60 cm and may have a cohesive slab above. Shallow snowpack areas and moraine features may also have weak facetted snow near the ground that will require time and some warming to strengthen.

Problems

Wind Slabs

Wind slabs may be lurking behind ridges and ribs.

Be cautious as you transition into wind affected terrain. >Use ridges or ribs to avoid pockets of wind loaded snow. >

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

A low probability/ high consequence persistent slab problem still exists. Investigate your local snowpack.

Dig down to find and test weak layers before committing to a big line. >Avoid exposed alpine faces, especially in the north of the region.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved, especially in the south of the region.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Jan 11th, 2016 2:00PM