Avalanche Forecast

Issued: Apr 1st, 2013 10:27AM

The alpine rating is moderate, the treeline rating is low, 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 - Timing or intensity of solar radiation is uncertain

Weather Forecast

The weather pattern starts to change as the dominating upper ridge weakens allowing a more onshore flow, bringing cloudy skies and light precipitation.Tuesday: Mix of sun and clouds. Alpine temperatures near 3.0 and freezing levels riding to 2400 m. Ridgetop winds will blow light from the West.Wednesday/Thursday: Mainly cloudy with light precipitation amounts. Alpine temperatures around zero degrees and freezing levels around 2100 m. Ridgetop winds light from the West.

Avalanche Summary

Glide cracks are opening up and releasing, use extra caution or just straight up avoid them. On Sunday a size 3.5 glide crack release occurred from a West aspect at 2300 m and ran to the valley bottom. Loose wet avalanches up to size 2 continue to be widespread. Avalanche control work using explosives triggered loose snow and slab avalanches up to size 2.5 on SE-SW aspects.

Snowpack Summary

Large cornices loom over many slopes. The upper 10 cm of surface snow has become moist and wet up to 2300 m, and melt-freeze conditions exist. Surface facetting and surface hoar (up to 12 mm) are prevalent on Northerly aspects.The surface snow overlies an old crust (down 50-60 cm) which exists up to ridge top. The bonds with the crust have gained strength in most places, and most 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. Wet slab avalanches are also possible, particularly on solar aspects where a crust or smooth ground cover exists.

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

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

1 - 5

Valid until: Apr 2nd, 2013 2:00PM