Avalanche Forecast

Issued: Jan 23rd, 2015 8:06AM

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

andrew jones, Parks Canada

Glacier.

Avalanche hazard will increase with the arrival of new precipitation and rising temperatures.

Summary

Weather Forecast

A moisture laden pacific system is moving inland. For today, expect up to 10cm of accumulation with moderate SW winds. Precipitation intensity increases tonight with 22mm expected by Saturday morning. Light snow continues throughout Saturday. The next main pulse arrives Sat evening with up to 30 mm by Sunday. Freezing levels to 1900m for Sunday.

Snowpack Summary

A 60cm slab sits on the Jan 15 surface hoar. It will be deeper in lee features where loaded by south winds. The Jan 15 was widespread, largest at treeline, and on solar aspects sits on a sun crust. Snowpack stability tests indicate it is likely to be triggered and propagate. The Dec 17 surface hoar is down 100-150cm.

Avalanche Summary

On Tuesday artillery control 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. Human triggered avalanches up to size 2.5 continue to occur in the region. Remote triggering from up to 300m has been reported.

Confidence

Timing of incoming weather systems is uncertain

Problems

Persistent Slabs

A 60cm+ thick cohesive slab now overlies a touchy surface hoar layer. Tests indicate that it may be triggered by human loads and likely to propagate widely as the slab stiffens. 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

Possible - Likely

Expected Size

1 - 3

Deep 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

Valid until: Jan 24th, 2015 8:00AM