Avalanche Forecast

Issued: Jan 12th, 2016 9:29AM

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.

swerner, Avalanche Canada

Purcells.

Forecast snowfall amounts are uncertain. If you receive less then 15 cm of new snow consider the danger ratings too high.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

The next Pacific frontal system will reach the Interior tonight spreading moderate precipitation amounts through Wednesday. Average snow amounts range from 15-25 cm by Wednesday afternoon. Ridgetop winds will be moderate-strong from the SW, alpine temperatures -7 and dropping. A split flow in the jet stream will guide subsequent Pacific storms south of B.C. bringing mostly dry and unsettled weather Thursday and Friday. The next storm will move onshore sometime Saturday.

Avalanche Summary

On Tuesday, reports indicated mostly sluffing up to size 1 from steeper terrain features.

Snowpack Summary

Up to 10 cm of recent low density snow overlies a variety of weak surfaces including surface hoar and facets. Storm and wind slabs are expected to build with forecast snow on Wednesday. The upper snowpack is generally loose and unconsolidated due to the current lack of slab properties, however there is now up to 30 cm sitting on a mix of surface hoar, facets, and sun crusts that were buried January 4th. In parts of the Purcells, two prominent layers of buried surface hoar continue to be reactive with hard sudden collapse results in snowpack tests down 30-60 cm. The mid and lower snowpack is generally well settled and strong.

Problems

Storm Slabs

Building storm slabs sit on a variety of weak layers making avalanche conditions touchy.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Dig down to find and test weak layers before committing to a big line. >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 13th, 2016 2:00PM