Avalanche Forecast

Issued: Dec 20th, 2013 8:30AM

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

ghelgeson, Avalanche Canada

Northwest Inland.

Forecasters are working with almost no 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 reef of the coast mountains will be stealing most of the action from the inland, but the region should still see a little bit of precip Saturday and then some warming on Sunday afternoon.Saturday: Freezing Level: Valley Bottom Precip: 1/3mm – 2/6cm Wind: Light, NWSunday: Freezing Level: 1600m Precip: Trace Wind: Mod gusting Extreme, WMonday: Freezing Level: 800m Precip: Nil Wind: Mod gusting Strong, W

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're relying on a shoe string worth of data for this forecast! There is significant variation in snow depths across the region. In the Smithers area the ski hill is reporting an 85 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

Wind Slabs

These wind slabs are probably getting old & tired at this point. I suspect that they may still be susceptible to human triggering on steep and/or convex features.

Use ridges or ribs to avoid pockets of wind loaded snow.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>Be careful with wind loaded pockets >

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

Triggering an avalanche on the crust/facet combo may still be possible, especially where the snowpack is thin and weak. Keep this lingering weakness in mind as you make terrain choices throughout your day.

Be aware of the potential for large, deep avalanches due to the presence of buried crust/facet combo.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Avoid convexities or areas with a thin or variable snowpack.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 21st, 2013 2:00PM