Avalanche Forecast

Issued: Apr 7th, 2015 10:44AM

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

ghelgeson, Avalanche Canada

Purcells.

Stay alert to conditions that change with aspect, elevation and time of day. Watch for clues like a moist or wet snow surface that indicate its time to find colder snow or head for home.

Summary

Confidence

Fair

Weather Forecast

WEDNESDAY: Freezing level starting at 1000m, rising to 2000m. Light N/NE winds at all elevations. No significant precipitation expected. Clear skies initially, cloud cover building in the afternoon.THURSDAY: Freezing level starting near 1500m, rising to around 2200m. Light W/SW winds at all elevations. Clear skies. No significant precipitation expected.FRIDAY: Freezing level starting at 1500m rising to 2200m. Light SW winds at treeline, moderate SW winds at ridgetop. No significant precipitation.

Avalanche Summary

Several cornice falls have been reported in the last few days, some of which have triggered avalanches on slopes below.

Snowpack Summary

The recent 10 to 25cm of storm snow was shifted by variable strong winds into wind slabs on lee slopes above 2000m. These wind slabs are probably growing old and tired. Cornices are large and touchy in some spots. The new snow sits over a crust which is generally becoming more supportive. Low elevations sport an isothermal snowpack, which is now capped by a refrozen crust.Persistent weak layers in the upper snowpack remain a lingering concern, although they seem to be slowly gaining strength. In the north of the region, the mid-March crust/facet layer is down 40-60cm. The mid-February crust/facet/surface hoar layer, down about 80 cm, may also still be reactive in isolated areas. Weak layers which formed earlier in the winter are also a concern in certain spots. Look for a revised snowpack description tomorrow. (April 8th)

Problems

Cornices

Steadily increasing temperatures over the latter half of the week will make cornices more prone to failure.

Cornices become weak with daytime heating, so you need to travel early on exposed slopes.>When traveling in the alpine, be SURE you're on the ridge, and not on a cornice. >

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 4

Loose Wet

Anytime previously dry/cool snow experiences the intense kiss of the spring sun, loose wet avalanches are likely. Increasing temperatures may even drive loose wet activity on high elevation north and east facing features as the week goes on.

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

Valid until: Apr 8th, 2015 2:00PM