Avalanche Forecast

Issued: Jan 10th, 2013 9:55AM

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

Avalanche Canada ghelgeson, Avalanche Canada

A conservative and cautious approach is required in the mountains this weekend.

Summary

Confidence

Fair

Weather Forecast

Friday: Moderate NE winds at ridgetop. Freezing level at valley bottom. No snow. 1500m temp: -12Saturday: Light W/NW winds at ridgetop. Freezing level valley bottom. No snow. 1500m temp: -16Saturday: Light NW winds at ridgetop. Freezing level valley bottom. No snow. 1500m temp: -16

Avalanche Summary

A natural cycle to size 2 was observed in the Castle backcountry on Wednesday. 

Snowpack Summary

The recent storm has deposited anywhere from 20-40cm of new snow. This has been accompanied by strong to extreme southwest winds, resulting in extensive windslab development in lee and open terrain. Due to the consistent winds, the slabbing extends well down onto slopes much lower than is normal. This new snow overlies significant snow depth and layer variabilities. Hard windslabs, hard pressed (windward slopes) snow and previous wind scour are all newly buried. In more sheltered areas the interface is small facets, surface hoar on sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. Snowpack tests on the surface hoar yield Sudden Planar results.The mid pack is well settled and strong. This overlies one or two crusts (location specific) with the higher crust being as shallow as 80cm below the surface. Concern lingers (unlikely) for triggering a deep slab avalanche in a shallow snowpack area or with a heavy trigger.

Problems

Wind Slabs

An icon showing Wind Slabs
Extensive windslabbing with the continuous strong winds.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Storm Slabs

An icon showing Storm Slabs
Where the storm snow is deeper than 20cm, expect a cohesive storm slab.
The new snow will require several days to settle and stabilize.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Jan 11th, 2013 2:00PM