Avalanche Forecast

Issued: Dec 21st, 2013 9:31AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs and Deep Persistent Slabs.

Avalanche Canada ghelgeson, Avalanche Canada

Forecasters are working without field data at this time. If you are traveling in the backcountry we'd love to hear about what you're seeing out there! forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Synopsis: The pattern switches to a more southwesterly flow over the next 24 hours. The Smithers area should see a bit of rain/snow while other snow holes in the region could see up to 20 cm at upper elevations.Sunday: Freezing Level: 1800m Precip: Snow & Rain 5/10mm 10 /20cm Wind: Mod gusting Extreme, SWMonday: Freezing Level: 900m Precip: Nil Wind: Strong, W Tuesday: Freezing Level: Valley Bottom Precip: Nil Wind: Lht W gusting Strong.

Avalanche Summary

A few small wind slabs just below ridge crest were reported on Dec. 15. No other avalanches have been reported. This likely speaks more to the lack of observations than actual conditions.

Snowpack Summary

We've received one observation from this region in the last week. As a result, you need to take this discussion with a grain of salt, so to speak.There is significant variation in snow depths across the region. In the Smithers area the ski hill is reporting an 89 cm base. Treeline depths vary between 100 - 180 cm.The region has picked up 5 - 20 cm of cold new snow over the last three days. Last weekend's storm finished very warm, as a result a crust can be found near the snow surface below 1100m. The best guess is that the last storm produced around 10 - 50 cm of snow. This snow now overlies the layer of facets/surface hoar that sit above old wind slabs and melt-freeze crusts which were formed during the December cold/dry spell. We don't have great wind stations in the region, but the coast saw a lot of strong wind during the last storm & I suspect this region was similarly hammered by wind. The mid and lower snowpack is still structurally weak due to facets, potentially even depth hoar and an early season crust near the ground.

Problems

Storm Slabs

An icon showing Storm Slabs
On Sunday wind will combine with snow, rain and warming temps to create a touchy storm slab that should increase in sensitivity throughout the day as new snow is added to our complex snowpack. Give yourself options for conservative terrain.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>The new snow will require a day or two to settle out and stabilize.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The likelihood of triggering an avalanche on the crust/facet combo is increased on Sunday.  It's most likely where the snowpack is thin and weak. Keep this lingering weakness in mind as you make terrain choices throughout your day.
Avoid convexities or areas with a thin or variable snowpack.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Be aware of the potential for large, deep avalanches due to the presence of buried crust/facet combo.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 22nd, 2013 2:00PM

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