Avalanche Forecast

Issued: Jan 10th, 2014 8:08AM

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

danyelle magnan, Parks Canada

Glacier.

The weather this weekend is looking intense! Choose your objectives carefully, and minimize your exposure to avalanche terrain when it starts dumping and wind starts howling.

Summary

Weather Forecast

A weakening front will continue to give light snow today, but we should have a lull in the weather this afternoon. Expect up to another 10cm today, with moderate to strong SW winds. Another system arrives overnight, bringing heavy snowfall. Up to 30cm are expected by the end of Saturday. On Sunday, heavy snowfall with strong winds are forecast.

Snowpack Summary

A new storm slab is building over top of various potentially weak snow surfaces. Up to 40cm overlies surface hoar, graupel and/or thin sun crusts on steep solar aspects. Last week's storm slab continues to bond, with only resistant planar results in tests. The lower snowpack is facetted but is showing signs of strength more typical for this region.

Avalanche Summary

Yesterday there were several natural avalanches observed east of Rogers Pass. They primarily occurred from steep, wind-loaded features. There were 5 size 2-2.5 avalanches from N aspects and one size 2.0 from a S aspect. Skiers reported sluffing in the top 20cm snow.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Storm Slabs

A new storm slab is developing. The new snow is still loose and unconsolidated, but with mild temps and continued loading by new snow it will become more of a concern. Heads up if the snow starts to feel slabby. Watch for sluffing on steep slopes.

Assess start zones carefully and use safe travel techniques.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

With lots of loose snow available to be transported, and sustained moderate winds above treeline, new windslabs are forming. In addition, cornices are becoming large and may fail triggering the slopes below.

Be cautious as you transition into wind affected terrain.Travel on ridgetops to avoid wind slabs on slopes below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

The persistent weak layers are now fairly deep in the snowpack. They will likely need a sizeable trigger, like an avalanche or a large chunk of cornice falling. They may be triggered from thin snowpack areas by a lighter trigger, like you.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Jan 11th, 2014 8:00AM