Avalanche Forecast

Issued: Mar 30th, 2013 9:57AM

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

swerner, Avalanche Canada

Kootenay Boundary.

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 5.0 and freezing levels 2500 m. Ridgetop winds light from the NW.Monday: Scattered clouds. Alpine temperatures 6.0 and freezing levels rising to 2600 m. Ridgetop winds blowing light from the NW.Tuesday: Cloudy. Alpine temperatures -1.0 and freezing levels falling to 2300 m. Ridgetop winds blowing light from the SW.

Avalanche Summary

Numerous loose wet avalanches up to size 1.5 seem to be the consistent theme these days. Be aware of overhead hazards such as cornice fall. It is likely that natural loose wet, or wet slab avalanche activity will continue.

Snowpack Summary

Large cornices loom over many slopes. The upper 10 cm of surface snow has become moist up to 2300 m, and melt-freeze conditions exist. Surface facetting and surface hoar (up to 12 mm) are prevalent on Northerly aspects.A cohesive slab overlies an old crust (down 50-60 cm) which exists up to ridge top. The crust appears to have gained some strength in most places, and some test results are showing resistant planar fracture characteristics. Snowpack variability exists, it is important to dig down and test weak layers before diving into your line.

Problems

Loose Wet

Solar aspects are likely to see loose wet avalanches when the sun comes out and temperatures start to warm.

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

Very Likely

Expected Size

1 - 4

Cornices

With solar radiation and warm daytime temperatures, cornices may become unstable. There is a chance the weight of a cornice dropping onto the slope below could trigger an avalanche on the Mid-March crust.

Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 5

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