Avalanche Forecast

Issued: Mar 26th, 2013 10:02AM

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

swerner, Avalanche Canada

South Rockies.

Be aware of changing conditions with daytime warming and sunny skies. Watch solar slopes and overhead hazards.

Summary

Confidence

Good

Weather Forecast

Mainly clear skies with some high-mid cloud cover and temperatures steadily increasing by the weekend.Wednesday: Â Mix of sun and cloud. Treeline temperatures near -2.0. Freezing levels rising to 2200 m in the afternoon and then falling to 1200 m overnight. Ridgetop winds will be light from the West.Thursday/Friday: Partial cloud cover, then mostly sunny on Friday. Treeline temperatures near -1.0. Freezing levels will ride to 2200 m and then falling back to 1500 m overnight. Ridgetop winds will be light rom the SW.

Avalanche Summary

No new natural avalanche activity.

Snowpack Summary

Cornices are large and will likely become weak due to strong solar radiation and warming temperatures. Surface snow may become moist or wet up to 2200 m, especially on solar aspects. Melt-freeze conditions exist. Approximately 40-70 cm of settling storm snow sits on top of a buried rain crust down 50 cm and exists up to around 2100 m. In areas near Sparwood, the new snow initially bonded poorly to this crust, and a few large avalanches were observed that likely released on this layer. In the North Elk Valley, the bond at the crust was reported to be fairly good. Generally, this interface has now become stronger for all parts of the region. However, 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.Recent wind slabs exist in the immediate lee of ridge lines and terrain features.

Problems

Cornices

Large looming cornices exist on most ridgelines. Cornices may become weak under the influence of the sun. They are a hazard in themselves and they could trigger slopes below.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Loose Wet

Clear sunny skies and warmer afternoon temperatures 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.>Watch for wet loose or slab activity.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Wind Slabs

Wind loaded and cross-loaded slopes can still be found at treeline and alpine elevations. There is still a chance a small wind slab avalanche could step down to the March 16th rain crust.

Avoid cross loaded features, especially in the alpine.>Whumpfing is direct evidence of a buried instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Mar 27th, 2013 2:00PM