Avalanche Forecast

Issued: Nov 22nd, 2012 9:06AM

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

swerner, Avalanche Canada

South Rockies.

This bulletin is based on limited data. Local variations in conditions are likely to exist. Check out the Forecasters Blog for further details on interpreting early season bulletins.

Summary

Confidence

Poor - Due to limited field observations for the entire period

Weather Forecast

A Pacific frontal system will be dominating the coastal regions tonight. This system will move into the Interior regions on Friday bringing light â€“moderate snow accumulations.Â Through the weekend a NW flow will set up, bringing cooler, dryer conditions and partially sunny skies. Freezing levels remain in valley bottom through the period.Friday: Alpine -5, snow 5-10 cm, winds SW 30 â€“ SE 40 km/hr.Saturday: Alpine -10, snow 2- 5 cm, winds W 20 km/hr switching NW.Sunday: Alpine -15, snow 5 cm, winds NW 10km/hr.

Avalanche Summary

No current avalanche observations have been submitted. If you and your friends have been out exploring and riding in the backcountry, and have some observations to share please send us an email to forecaster@avalanche.ca.

Snowpack Summary

Snowpack observations and information are extremely limited, and conditions across the region vary. In the alpine I suspect anywhere from 50-100 cm of snow. Storms slabs and wind slabs likely exist in alpine and treeline elevations. An early season (Nov 8) rain crust has been reported to exist around 2000 m and above on NW-NE aspects. I have no further information in regards to this crust, how deep its buried or reactive it may be. I do know that it has been a reactive sliding layer in other regions to the North, which makes me suspect this problem may extend into the South Rockies.Snow depths at treeline are roughly sitting around 30-50 cm in depth, and below treeline snow levels may still be below threshold.

Problems

Wind Slabs

Wind slab instabilities likely exist and may be touchy to rider triggers. Wind slabs can be found on lee slopes and behind terrain features. Storm slab instabilities may still exist on all aspects, and require a couple days to settle out.

Avoid cross loaded slopes at or above treeline.>Be alert to conditions that change with elevation.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

An early November rain crust is buried down approximately 40-60 cm at treeline and in the alpine. Information is almost non-existent, but adjacent regions have been seeing avalanche activity occur on this layer.

Be aware of thin areas that may propagate to deeper instabilites.>Ride slopes one at a time and spot for your partners from safe locations.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Valid until: Nov 23rd, 2012 2:00PM