Avalanche Forecast

Issued: Dec 29th, 2015 7:40AM

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.

Conditions are variable across the Purcells. In isolated areas, a persistent weak layer may still be reactive to human triggers. Take the time to investigate your local snowpack.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

A cool, dry spell is starting. Expect light northerly winds, sun and slightly milder temperatures in the alpine; and cloud and cold temperatures in the valleys.For more details check out http://www.avalanche.ca/weather.

Avalanche Summary

Over the last few days, several small loose dry avalanches and one size 1.5 wind slab have been observed. Persistent slabs were last triggered about a week ago. Unfortunately these types of problems don't heal quickly, so they remain on our radar.

Snowpack Summary

20-30 cm of low-density snow typically overlies a well-settled mid and lower snowpack. Surface hoar and near-surface facets may be mingled within the upper few cm. Storm slab properties may change and become more cohesive as the alpine gets some sun and warmer temperatures. Wind slabs, found in the lee of ridges and ribs, are still reactive in some spots and healing in others.A weak layer which was buried in early December is down about 40-100 cm. At and below treeline, it mainly consists of large surface hoar. At higher elevations, it consists of a sun crust, facets, and/or small surface hoar. This layer is still reactive in some snowpack tests and has produced at least one human-triggered avalanche in the last week. The persistent slab is a low probability, high consequence problem. Below this layer, the snowpack is thought to be generally strong and well-settled.

Problems

Wind Slabs

Soft wind slabs may be reactive to the weight of a person below ridges and ribs.

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

Expected Size

1 - 2

Persistent Slabs

A weak layer buried about 40-100 cm down remains reactive in snowpack tests in some areas. It has produced avalanches within the last week.

Dig down to find and test weak layers before committing to a big line. >Conditions are greatly improved, but be mindful that persistent weak layers are still present. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Dec 30th, 2015 2:00PM