Avalanche Forecast

Issued: Feb 7th, 2015 9:02AM

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

ghelgeson, Avalanche Canada

Northwest Inland.

The danger has come down slightly, but the snowpack needs more time to adjust before we start to size up more challenging objectives.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Clear and dry weather is forecast for the period. No precipitation is expected. Winds should decrease Saturday afternoon, but they remain strong SW at upper elevations Sunday. Monday and Tuesday look the same, but all bets are off for Wednesday. The current models show the freezing level rising to 2000m. Too early to say how that will play out.

Avalanche Summary

I suspect large natural avalanches were running Friday, but we do not have any observations from treeline/alpine elevations where the action is at.

Snowpack Summary

The storm has produced approximately 30 to 70 cm of new snow accompanied by strong to extreme winds out of the E through SE. There are a number of weak layers in our snowpack, this storm should be a good test for all of them. In places the new storm snow sits on the early February surface hoar, little is known about the distribution of this interface. The late January crust is probably down 60 to 100cm in the south, it's likely shallower in the north. The mid-January rain crust(with some spatially spotty surface hoar on top) is down over a meter. It might still be a problem in thin snowpack areas. The crust/facet combination from November can be found near the ground. It's not an easy snowpack to work with, we'd greatly appreciate your observations via the Mountain Information Network.

Problems

Storm Slabs

Strong SW winds may continue to fuel the natural avalanche cycle at upper elevations, even if they back off the snowpack still needs some time to adjust to the 30 to 70cm of new snow.

The new snow will require several days to settle and stabilize.>Be very cautious if you decide to step out of simple terrain.>Be mindful of the wind. If it's moving snow around natural avalanches are likely still possible.>Slopes receiving direct sun for the first time since the storm could produce natural avalanches.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 7

Deep Persistent Slabs

No observations mean there's significant uncertainty concerning the deeper problem layers in the snowpack. I would manage this by assuming that every slope above treeline has the potential to produce a very large and destructive avalanche.

Be aware of the potential for large, deep avalanches due to the presence of buried crusts and/or surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

4 - 7

Valid until: Feb 8th, 2015 2:00PM