Avalanche Forecast

Issued: Apr 2nd, 2013 10:19AM

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

jlammers, Avalanche Canada

South Rockies.

Be alert to conditions that change with daytime warming. Danger ratings are likely to exceed posted levels if solar radiation is strong, especially at treeline and below.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Wednesday

Weather Forecast

Wednesday: Overcast skies with very light snowfall / Light southwest winds / Freezing level at 2200mThursday: Moderate snowfall/rain developing late in the day / Moderate southwest winds / Freezing level at 2400mFriday: Moderate to locally heavy snowfall/rain / moderate southwest winds / Freezing level at 1800m

Avalanche Summary

On Monday, numerous wet slab avalanches and glide crack releases were reported up to size 3 from South-West aspects. As long as temperatures are warm and solar radiation is high, I would expect more of this activity.

Snowpack Summary

We are in a classic spring melt-freeze cycle. The surface snow becomes moist up to 2200m on all aspect and to ridgecrest on sun-exposed slopes. Large cornices are becoming weak due to strong solar radiation and warming temperatures. Surface hoar growth and surface facetting is happening at night on high sheltered, northerly aspects. Isolated wind slabs exist in the immediate lee of ridge crests and terrain featuresA buried rain crust can be found down 50 cm and exists up to around 2100 m. Although unlikely, a large trigger such as a cornice fall or warming on a solar aspect could cause this layer to fail.

Problems

Loose Wet

Intense solar radiation is unlikely on Wednesday. If the sun is strong, however, loose wet avalanches can be expected on sun-exposed slopes.

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

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Wet Slabs

Large wet slab, and glide crack releases may occur in the heat of the day if the sun is shining.

Watch for wet slab activity with forecast warm temperatures.>

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 6

Cornices

Large looming cornices exist on most ridgelines. They are a hazard in themselves and they could trigger slopes below.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Apr 3rd, 2013 2:00PM