Avalanche Forecast

Issued: Mar 30th, 2013 9:41AM

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

swerner, Avalanche Canada

South Rockies.

Danger could INCREASE TO CONSIDERABLE with intense radiation on south and west aspects, especially at treeline and below. Be aware of how the warm weather is changing the snowpack.

Summary

Confidence

Good

Weather Forecast

A dominating high pressure system with sunny skies, rising freezing levels and light winds continues through to Monday. The pattern will start to deteriorate by Tuesday, showing increased cloud and grey skies with no precipitation. Sunday: Few to scattered high cloud. Alpine temperatures 3.0 and freezing levels 2700 m. Ridgetop winds light from the NW.Monday: Scattered clouds. Alpine temperatures 4.0 and freezing 2700 m. Ridgetop winds blowing light from the NW.Tuesday: Cloudy. Alpine temperatures 2.0 and freezing levels falling to 2500 m. Ridgetop winds blowing light from the SW.

Avalanche Summary

Small loose wet avalanches up to size 1.5 were reported.

Snowpack Summary

The surface snow has become moist or wet up to 2200 m, especially on solar aspects. Spring-like, melt-freeze conditions exist. Surface hoar and surface facetting is forming on sheltered, northerly aspects, especially at higher elevations. Cornices are large and weak during daytime warming. Pockets of wind slab may still exist in the immediate lee of ridge lines and terrain features. A buried rain crust can be found down 50 cm and exists up to around 2100 m. The bond of this snow to the crust has shown variability though the region. It is important to dig down and test weak layers before dropping into your line. A large trigger such as a cornice fall or a skier/sledder hitting the sweet spot, could potentially trigger a large avalanche on this layer.

Problems

Cornices

Large looming cornices exist on most ridgelines. They are a hazard in themselves and they could trigger slopes below. Wind loaded and cross-loaded slopes may still be found at upper elevations.

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

Likely

Expected Size

2 - 5

Loose Wet

Warmer afternoon temperatures and sunshine may promote deterioration within the upper snowpack. If surface snow becomes moist or wet, loose wet avalanches are likely. Watch solar aspects.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Valid until: Mar 31st, 2013 2:00PM