Avalanche Forecast

Issued: Nov 24th, 2017 4:27PM

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

Kootenay Boundary.

Lookout for small 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 / Light southerly ridgetop winds / Freezing level around 1500 mSUNDAY: 10-20 mm rain / Moderate to strong southwesterly ridgetop winds / Freezing level around 2500 mMONDAY: Cloudy with isolated flurries / Light to moderate westerly ridgetop winds / Freezing level around 1500 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. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 100+cm in the alpine, 50-100cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks. Recent heavy rain to the mountaintops has rapidly shrunk the snowpack and has transitioned much of the snowpack from dry to moist snow. The major feature in the snowpack is a crust which was formed at the end of October can be found approximately 30cm above the ground. 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 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, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Recent rain to mountaintops 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.Use increased caution in areas which did not form a surface crust.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

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