Avalanche Forecast

Issued: Nov 24th, 2013 8:28AM

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

rbuhler, Avalanche Canada

Kootenay Boundary.

This bulletin was created using very limited field data. Significant variation in snowpack structure is likely to exist across the region. If you are out in the mountains, please send your observations to forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

An upper ridge of high pressure dominates until Tuesday resulting in dry conditions, light alpine winds, and mostly sunny conditions. A temperature inversion exists over most of the Kootenay-Boundary region with a layer of warm air sitting at mountain-top elevation. On Wednesday a weak upper trough will replace the high pressure system causing increased cloud cover andÂ the possibility of light snowfall.

Avalanche Summary

We have received limited reports of pin-wheeling and small loose snow avalanches releasing on steep, sunny aspects during afternoon warming.

Snowpack Summary

80-110cm of snow is typical at treeline although observations are limited and this amount may vary across the region. Roughly 60 to 70cm of well settled storm snow is now sitting on the October crust located just above the ground. Little is known about the reactivity of this crust; however, limited reports suggest that the crust interface is well bondedThe current temperature inversion is causing the snow surface to melt in the alpine. Sun exposed slopes are undergoing daily melt-freeze cycles. A surface crust is also being reported below 1700m. Large SH is forming on all aspects but is melting on south aspects during the daytime warming. If you are traveling in the mountains, now is a good time to make note of these surface conditions which may become persistent weak layers once buried by new snow.

Problems

Persistent Slabs

Limited reports suggest it has become more difficult to trigger a persistent slab. However, if an avalanche is triggered, it has the potential to be large and destructive.

Caution around convexities or areas with a thin or variable snowpack.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Loose Wet

Loose wet activity will become more likely in the afternoon under sunny skies. Watch for increased reactivity on steep, sun-exposed slopes.

Avoid steep sun exposed slopes.>Watch for clues that the snowpack is warming up (like sluffing off of cliffs, pinwheeling) . >

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Nov 25th, 2013 2:00PM