Avalanche Forecast

Issued: Mar 21st, 2015 8:01AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs, Loose Wet and Persistent Slabs.

andrew jones, Parks Canada

Glacier.

New snow, strong winds and warm temperatures continue to drive the hazard up. Stability will improve once colder temperatures return. Until then, choose conservative objectives.

Summary

Weather Forecast

For today, an upper level trough will bring light snow flurries with up to 12cm of accumulation above 1800m and rain below. Ridge winds will be moderate SW with occasional gusts to 70km/hr. Light precipitation continues tonight with the approach of an incoming cold front. Freezing levels are expected to drop1300m.

Snowpack Summary

30cm of new snow has buried a variety of surfaces from sun crusts to reactive wind slabs. The upper snowpack is a complex mix of crusts, weak facetted snow and surface hoar. Below 1900m the top 30cm of the snowpack is moist as sits on a supportive crust. Warm overnight temperatures prevented a solid re-freeze of the snow in the valley bottom.

Avalanche Summary

A field team on Grizzly Shoulder heard several natural avalanches occurring up the Connaught Creek drainage as daytime temperatures warmed. While descending Grizzly Shoulder the field team ski cut several loose moist avalanches up to size 2, entraining moist snow and running far and fast on the March 14 crust. Several moist naturals in HWY paths.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Storm Slabs

New snow continues to load the storm layer which is 40-60cm deep. In exposed lee areas, buried wind slabs within the storm snow will be difficult to identify visually. New snow, wind and warm temperatures will increase the hazard.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Avoid avalanche terrain during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Wet

Warm overnight temperatures and ongoing rain continues to weaken the snowpack at lower elevations. Loose wet avalanches are easily triggered by skiers. These avalanches have the potential to run far and fast, especially where buried crusts exist.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The upper snowpack is complex with a multitude of crusts, weak facetted layers, and surface hoar. Large slab avalanches continue to sporadically occur on these layers. Cornices are large and fragile and if they fail provide a large trigger.

Be aware of the potential for large, deep avalanches.Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

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