Avalanche Forecast

Issued: Mar 30th, 2015 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Loose Wet and Cornices.

tim haggarty, Parks Canada

Waterton Lakes.

Difficult travel conditions exist with very little snow remaining below 1900m and crusts to Treeline. Winter is hanging on in the alpine however and slab formation will continue with small amounts of incoming snow and dropping temperatures this week.

Summary

Weather Forecast

Heating that peaked Monday will persist until midday Tuesday when freezing levels will drop to below treeline for the rest of the period. Expect isolated convective snow flurries for the period dropping trace ammounts. Winds will remain west and moderate through Wednesday when the will diminish to light for Thursday.

Snowpack Summary

Treeline and below there is wet snowpack capped by a thin crust on all aspects. Below 1900m very little snow remains. In the Alpine winter is hanging on although a rain crust now exists to about 2400m. Recent snowfall and West winds have formed fresh windslabs and cornices are large.

Avalanche Summary

Warming and rain to 2400m last week created widespread loose wet avalanches to ridgetops on solar slopes and to Treeline on shaded slopes. Heating and strong west contributed to several cornice failures, a few of which triggered significant slabs to size 2.5 on North facing slopes in the alpine.

Confidence

Due to the number of field observations

Problems

Wind Slabs

Although thin in many areas, there are some significant slabs that have grown along the ridge crests. New snow and continued West winds will continue to build these. Do not get caught by these while pushing to ski dry snow.

Use caution in lee areas in the alpine and treeline. Recent storm snow has formed touchy slabs.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

As heating breaks down thin surface crusts the entire moist snowpack below can become available to failure especially at lower elevations or on solar slopes. Watch overnight freezing levels closely and monitor the effects of the sun on the snow.

Travel early before the heat of the day, and avoid big slopes in the afternoon.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Strong winds have built large cornices on ridgetops that could fail with the warm temperatures and sun exposure. Recent failures have triggered significant alpine slabs that ran to below treeline elevations.

Cornices become weak with daytime heating. Pay attention to overhead hazards like cornices.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 2nd, 2015 4:00PM