Avalanche Forecast

Issued: Jan 21st, 2015 8:03AM

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

danyelle magnan, Parks Canada

Glacier.

Cautious terrain selection and good group management are essential right now. A touchy layer, with remote triggering potential means that you need to be aware of who is above and below you, minimize your exposure, and regroup in safe spots.

Summary

Weather Forecast

Today expect a mix of sun and cloud, with a high of -6'C and light to moderate SW winds. Light flurries are expected to begin overnight and continue through Thursday with freezing levels rising to 1400m. On Friday the first of a series of fronts moves into the region. Up to 30cm of snow are forecast by Saturday morning with strong W'ly winds.

Snowpack Summary

78cm fell over 5 days, settling into a 60cm lab over the Jan 15 SH. This slab will be deeper in lee features where it has been windloaded by moderate S winds. This surface hoar was widespread, observed well into the alpine and on solar aspects sits on a sun crust. The December 17 surface hoar layer is down 100-150cm sitting on a crust below 2100m.

Avalanche Summary

Artillery control yesterday triggered over 30 size 2 to 3.5 avalanches from all aspects between 17-2700m. Notables were size 3.5's from the W face of Cheops and off Mt Tupper that ran into the creeks. Avalanches up to size 3 have been observed in the backcountry. Human triggered avalanches continue in the region with remote triggering up to 300m.

Confidence

Problems

Persistent Slabs

A 60cm+ thick cohesive slab now overlies a very touchy surface hoar layer. Tests indicate that it is likely to propagate if triggered, and avalanches have been remotely triggered from up to 300m away.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

A surface hoar layer, down 1-1.5m, that was buried in mid December continues to be reactive. Avalanche control had a few avalanches stepping down to this layer, even in areas where it had been previously controlled. The new load may wake it up again.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 4

Wind Slabs

Strong southerly winds during the storm, with lots of low density snow available for transport, will have formed windslabs in lee areas. These deep pockets of windslab may overlie the touchy surface hoar layer.

Be cautious as you transition into wind affected terrain.Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 22nd, 2015 8:00AM