Avalanche Forecast

Issued: Mar 27th, 2013 4:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Deep Persistent Slabs, Cornices and Loose Wet.

mike eder, Parks Canada

Jasper.

If the skies are clear, expect the avalanche danger to increase in the afternoon. Serac fall may result from the warming temperatures on higher alpine climbing routes. Pay attention to overhead hazards and start your trip early in the day.

Summary

Weather Forecast

The skies will remain mostly clear and occasional high clouds in the afternoon through to the weekend. Some light sporadic snow flurries may come on the weekend with only trace accumulations. Temperatures will have high diurnal changes with strong solar radiation in the afternoons with freezing levels reaching 2000 meters.

Snowpack Summary

A variable thick slab exists in alpine and treeline locations on a variety of aspects. It is over a strong midpack except in shallow locations where you could trigger basal facets near the ground. A suncrust with varying thickness and strength exists at all elevations on steep South facing aspects. Below treeline, the crust breaks down by midday.

Avalanche Summary

Numerous loose snow avalanches were observed on steep South through West aspects at all elevations in the Icefields areas. They originate from steep rock bands and gully features where the sun heats the rocks. Below treeline, where the snowpack is thin, isothermal conditions are developing.

Confidence

Timing or intensity of solar radiation is uncertain on Friday

Problems

Deep Persistent Slabs

This continues to be the main concern with last week's avalanche activity showing deeper slabs that were sliding full depth on weak facets and in windloaded gully features on predominantly Northeast through to Southeast aspects.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Cornices

Cornices will become increasingly prone to failure as the days get warmer. A cornice failure could provide a heavy trigger for an avalanche on the slopes below. Pay attention to what is above you and the temperatures during the day.

Pay attention to overhead hazards like cornices.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Loose Wet

The sun is warming the rocks on steep rock cliffs and gully features on Southerly aspects. Loose snow avalanches are starting in these features at all elevations later in the day. Cloud cover will determine if this occurs during the day.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 28th, 2013 4:00PM