Avalanche Forecast

Issued: Mar 20th, 2014 8:07AM

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

danyelle magnan, Parks Canada

Glacier.

We are expecting to get some sun though the weekend. Even a little bit of solar radiation may be enough to trigger the storm slab, or cause a cornice to fail and trigger deeper layers. Minimize your exposure during sunny periods.

Summary

Weather Forecast

Today should be mostly cloudy with flurries. Temps will range from -7 to -15'C with moderate westerly winds. Friday should be cloudy with sunny periods, flurries will continue through the day. Saturday the flurries and the wind will taper off, with a mix of sun and cloud.

Snowpack Summary

The recent storm snow is settling, with various layers within it that are resistant when they fail with moderate force. Both the Mar 13 (down ~50cm) and the Mar 2 (down ~1m) crust/surface hoar layers are becoming patchy but reactive in snowpack tests where they exist. The Feb 10-Jan22 layers are down 1.5-2m and continue to show step down potential.

Avalanche Summary

Natural activity in the highway corridor has tapered off with cloud cover. A size 2 natural avalanche was reported from the Hospital Knob area of Connaught.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

The recent storm snow is settling into a cohesive slab, particulary in wind affected areas. Various weak layers within, and just below, the slab exist and may be triggered by skiers or snowboarders. It may become more reactive during sunny periods.

Be cautious as you transition into wind affected terrain.Be increasingly cautious on sun exposed slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

This layer is patchy which makes it difficult to predict. It is likely to be most reactive on solar aspects where it is comprised of a sun crust with surface hoar. If triggered it has properties and is deep enough to result in a large avalanche.

Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

The late Jan/early Feb persistent weak layer is still active. Very large and impressive avalanches have been triggered by rapid loading during storms, avalanche control, and skiers remotely triggering (fortunately in a safe spot) from shallow areas.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Mar 21st, 2014 8:00AM