Avalanche Forecast

Issued: Nov 25th, 2014 8:56AM

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

Avalanche Canada rbuhler, Avalanche Canada

Stormy weather will drive avalanche danger up this week. It's a good time for riding low angle slopes and avoiding overhead exposure.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

A warm front will move over the southern part of the province midday Wednesday resulting in mild temperatures and moderate to heavy precipitation. This will persist through Thursday before an Arctic front pushes down from the north on Friday. There is some uncertainty regarding freezing level extents and as a result the Northern Purcells may not see the warmer temperatures.Tues. Night/Wednesday: Precipitation 8-12mm, freezing levels starting at valley bottom rising to around 1500m late-Wednesday, ridgetop wind light-moderate SW-WWeds. Night: Precipitation 8-12mm, ridgetop wind moderate SWThursday: Precipitation 10-20mm, freezing levels rising as high as 2000m, possibly lower in the north, ridgetop wind strong SWFriday: A mix of sun and cloud, snow flurries possible, freezing level valley bottom, ridgetop wind light variable

Avalanche Summary

Currently there are no recent avalanche reports. It's likely that there is enough snow at higher elevations for avalanches, particularly in wind loaded alpine features. Stay alert to changing conditions and signs of unstable snow like recent avalanches, significant loading by wind or snowfall, whumpfing or cracking, or rapid warming.

Snowpack Summary

This is an estimate of what the snowpack may look like based of a few observations and previous weather. If you plan on riding in avalanche terrain be sure to supplement this with your own observations and please pass along any data you collect (forecaster@avalanche.ca).Around 30-40 cm of recent storm snow has fallen in the past few days. This new snow may be sitting on a layer of surface hoar and/or a sun crust (similar to the South Columbia). Below this you will likely find a 15-25cm thick layer of sugary facets, which is sitting on a solid rain crust from early November. Recent strong and variable winds may have created dense wind slabs in exposed terrain. The average treeline snowpack depth is around 60-100cm. The snow probably tapers off pretty quickly as you drop below treeline. Watch out for exposed (or lightly buried) obstacles like stumps, rocks, logs, and open creeks.

Problems

Storm Slabs

An icon showing Storm Slabs
The developing storm slab sits on a touchy weak layer and is expected to become very reactive with additional storm loading. Recent wind loading has created wind slabs in leeward features which are expected to be very touchy.
Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>Avoid freshly wind loaded features.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Loose Dry

An icon showing Loose Dry
Be cautious of loose sluffing from steep terrain as new snowfall continues. Rain on Thursday may result in loose wet avalanches at lower elevations.
Be cautious of sluffing in steep terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Nov 26th, 2014 2:00PM