Avalanche Forecast

Issued: Jan 15th, 2014 8:09AM

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

danyelle magnan, Parks Canada

Glacier.

The snowpack was rapidly loaded over the past week and will need to time to adjust. Over the next few days the new snow will get it's first punch from the sun; often a trigger. Minimize your exposure to cornices and overhead avalanche terrain.

Summary

Weather Forecast

Light flurries are possible this morning, with strong ridgetop winds, and freezing levels possibly rising to 1500m today. We may see some clearing later today as a ridge of high pressure builds. On Thurs expect mostly clear skies, with the first punch of solar to the new snow, alpine temps of -1 and freezing levels rising to 1900m by Friday.

Snowpack Summary

Over 1m of snow fell in the last week, burying a surface hoar/graupel layer. Strong winds during the storm formed slabs in exposed areas at all elevations. Rain below 1300m formed a crust. The mid pack is well settled with the Nov28 surface hoar layer down around 2m where present. The facetted base is showing signs of strengthening.

Avalanche Summary

No new natural avalanches were observed yesterday. On Monday, a widespread natural cycle occurred with avalanches to size 3.5. A size 3.5 from Dispatchers Bowl traveled 400m down Connaught creek. Artillery control triggered size 3.0 to 3.5 avalanches and a size 4.0 off Mt Green that released down to the glacial ice depositing snow onto the highway.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Strong winds have formed windslabs in open areas at all elevations. In many areas they have formed over lower density snow, which may be triggerable.

Be cautious as you transition into wind affected terrain.Stay off recent wind loaded areas until the slope has had a chance to stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Storm Slabs

Over a meter of new snow, combined with high winds and rising temps, have created a storm slab. It is sitting over snow that is much lighter, including a buried surface hoar layer. This slab will need some time to settle and bond.

Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Persistent Slabs

The recent avalanche cycle showed the reactivity of the snowpack to rapid loading and its capability to produce large avalanches. Until the snowpack adjusts to the new load these layers may be reactive. Be cautious in areas that have not avalanched.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 4

Valid until: Jan 16th, 2014 8:00AM