Avalanche Forecast

Issued: Jan 2nd, 2014 8:25AM

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

Avalanche Canada ghelgeson, Avalanche Canada

A number of significant avalanches have occurred in the north of this region and just beyond its northern boundary. Check the forecaster blog. Use caution if traveling in the backcountry at this time.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

Storm totals should be in the 10-25cm range with the most intense precipitation occurring on Thursday night. The freezing level drops after the storm and a ridge of high pressure looks to dominate for the foreseeable future.Thursday Night: Freezing Level: 1000m; Precip 5/15mm 5/20cmFriday: Freezing Level: 900m; Precip: 2/5mm 2/10cm; Wind: Mod NWSaturday: Freezing Level: Valley Bottom; Precip: Nil; Wind: Mod, NW Sunday: Freezing Level: Valley Bottom; Precip: Nil; Wind: Light, Var.(Forecasted wind speeds are at 2000m)

Avalanche Summary

A number of significant avalanches have been reported from the north of this region and just beyond its boundary to the north. One very large (size 3) avalanche was reported on Tuesday on a N aspect at 2200 m from relatively gentle terrain with a fracture depth of 100 cm. Two large (size 2) avalanches were reported from near Golden on Monday, likely triggering buried surface hoar from 10-Dec down around 50 cm. A size 3 natural avalanche was reported from the Bugaboos on Sunday on a NE aspect at 2650m, triggered by a cornice release that pulled out a large slab all the way to ground on the slope below. Outside the boundary of this region to the north of Golden, there was an incident in the Hope Creek drainage, where four people were involved (with two sustaining injuries) in a size 3 avalanche in an alpine feature on a NE aspect. Avalanche activity on Wednesday was limited to small wind slabs.

Snowpack Summary

Up to 25 cm of recent storm snow has been redistributed by moderate to strong northwest and southwest winds. In the upper metre of the snowpack a couple of persistent weak layers exist. The upper one comprises surface hoar and is buried around 40-50 cm. The lower one comprises a facet/crust combo and is buried 80-100 cm. Both interfaces give variable results with snowpack tests, but professional operators are treating them with caution.A bigger concern, especially in the Northern part of the region is a layer of weak sugary depth hoar crystals at the base of the snowpack that lie above a crust from early October. Several large avalanches in the last 10 days have been attributed to failures at this layer. Wide propagations on relatively gentle terrain have been noted, as well as a tendency for seemingly disconnected slopes to become connected by one large avalanche.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The most likely place to trigger a deeper layer is on a steep, convex, north-facing slope in an area with a relatively shallow snowpack.
Be aware of the potential for large, deep avalanches.>Avoid convexities or areas with a thin or variable snowpack.>Avoid thin, rocky or sparsely-treed slopes.>Large human triggered avalanches have occurred after riders found stable results from snowpack testing. Large features, especially in the north of the region, should be avoided at this time.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 6

Persistent Slabs

An icon showing Persistent Slabs
A weak layer buried around 50 cm has become reactive and can be readily triggered, especially at higher elevations on a variety of aspects.
Good day to make conservative terrain choices.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Storm Slabs

An icon showing Storm Slabs
New storm snow has been poorly bonding to the existing snowpack. Forecast new snow and winds will increase the likelihood of triggering an avalanche.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>The new snow will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 4

Valid until: Jan 3rd, 2014 2:00PM