Avalanche Forecast

Issued: Mar 29th, 2017 4:41PM

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

triley, Avalanche Canada

South Rockies.

Avalanche danger will increase if the the sun comes out and we get strong solar radiation combined with high freezing levels.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Thursday

Weather Forecast

Overnight: Flurries or light snow with strong westerly winds and freezing at 1300 metres by morning. Thursday: Mix of sun and cloud with periods of strong solar radiation. Light winds with daytime freezing up to 1800 metres. Friday: Mostly sunny with light winds and daytime freezing up to at least 2300 metres. Saturday: Unsettled with flurries or light snow, not much of a re-freeze below 2000 metres. Westerly winds developing during the day.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

A few more cm of new snow overnight, combined with gusty southwest winds has developed new wind slabs in the alpine and at treeline. Over the past several days we've had 10-30 cm of heavy snow at higher elevations, which sits on a thick hard crust that is quite solid above 1700m. Below the new snow and crusts, roughly 50-90 cm of snow sits above the February crust and facet interfaces. In some areas there may still be a poor bond to these interfaces. The bottom third of the snowpack is composed of weak facets and full-depth avalanches over this basal weakness remain a concern, and may be triggered by large loads (eg: cornice fall) or warm temperatures (eg: full exposure to the sun).

Problems

Wind Slabs

New wind slabs have developed in the alpine and at treeline. Wind slabs may not be well bonded to old surface crusts.

Use ridges or ribs to avoid pockets of wind loaded snow.If triggered, wind slabs may step down to deeper layers and result in large avalanches.Be alert to conditions that change with elevation and aspect.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Watch out for wet snow at lower elevations or on sunny slopes if the sun comes out during the day.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Heavy triggers such as a cornice fall or wind loading are potential triggers for large avalanches on deep weak layers. Be aware of overhead hazard, and do not linger in avalanche paths at lower elevations.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Minimize exposure to sun exposed slopes when the solar radiation is strong.Recognize and avoid avalanche runout zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Mar 30th, 2017 2:00PM