Avalanche Forecast

Issued: Nov 24th, 2015 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 Deep Persistent Slabs.

ghelgeson, Avalanche Canada

Purcells.

This forecast is based off a pretty meager set of observations. If you're out, please let us know what you're seeing via the Mountain Information Network. MIN

Summary

Weather Forecast

Arctic air slides down from the north resulting in clear skies and cooler than average temperatures for the forecast period. Strong N/NE winds at ridgetop are expected to continue through Wednesday afternoon, and then back off to light northerly for Thursday and Friday. We may see above freezing temperatures in the alpine beginning Friday evening, time will tell what the extent of this will be. No significant precipitation/snowfall expected for the forecast period. For a more detailed mountain weather forecast visit avalanche.ca/weather

Avalanche Summary

Control work in the north of the region Tuesday produced wind slabs to size 1 on high elevation south facing features.Â No other recent avalanche activity has been reported.

Snowpack Summary

Monday's storm snow fell on a variety of old surfaces including crust, surface hoar and old settled snow. Arctic air moving into the region has resulted in northerly winds which have formed small wind slabs on south facing features near ridge top. Warm temps and strong solar input formed a crust on south facing features which can be found underneath Monday's storm snow. There are at least three surface hoar layers in the snowpack buried on: Nov. 5th, Nov. 11th and Nov. 23rd. The first two have been largely unreactive. Facets may exist just above the ground on shaded slopes in the alpine.

Problems

Wind Slabs

Winds out of the north are likely driving wind slab formation on southerly features. These slabs are probably most problematic immediately lee of ridge crest, but you may encounter them in the right feature at treeline too.

Be cautious as you transition out of wind sheltered terrain.>Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

While many of our November wear layers are becoming less reactive, it's important to remember that there may be a weak layer of crust and facets near the ground. This is probably only a concern on north through east facing alpine features.

Now is a good time to dig a snow profile (or two) and figure out how the snowpack changes with aspect and elevation.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

4 - 6

Valid until: Nov 25th, 2015 2:00PM