Avalanche Forecast

Issued: Nov 24th, 2017 4:05PM

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

jsmith, Avalanche Canada

Cariboos.

Lookout for fresh wind slabs sitting on a hard crust in wind affected terrain at treeline and above. Due to limited data it is CRITICAL to supplement this information with your own observations. Please post your observations to the MIN.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

SATURDAY: Cloudy with flurries; 5-10 cm new snow in some areas / Light southwesterly ridgetop winds / Freezing level around 1500 mSUNDAY: 5-15 cm new snow in the afternoon with an additional 5-10 cm overnight / Moderate to strong southwesterly ridgetop winds / Freezing level around 2000 mMONDAY: Cloudy with isolated flurries / Light to moderate westerly ridgetop winds / Freezing level around 1300 m

Avalanche Summary

On Thursday, no new avalanches were reported in this region. However, we currently have very limited observations in this region. Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

A new crust was formed on Thursday as temperatures cooled and the rain soaked snow surface froze and then was covered by 5-10cm of snow at treeline and above. Wind re-distributing this new snow may have formed small wind slabs on lee features, such as below ridgetops and in gullies. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 200+cm in the alpine, 100-150cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks. The major feature in the snowpack is a crust which was formed around November 11th and can be found approximately 100cm down at treeline elevations. However, the new surface crust will temporarily reduce the likelihood of triggering on this layer. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.

Problems

Wind Slabs

Fresh wind slabs may have formed below alpine ridgetops in areas where the precipitation fell as snow on Thursday afternoon.

Be cautious as you transition into wind affected terrain.Avoid areas which have been loaded by new snow and wind.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Recent rain at most elevations combined with overnight cooling Thursday night has reduced the likelihood of triggering this layer. Areas in which the snowpack above this layer remained dry should be treated with increased caution.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Nov 25th, 2017 2:00PM