Avalanche Forecast

Issued: Apr 18th, 2013 10:59AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Thursday night and Friday: Light snowfall (higher amounts are more likely in the South end of the region) / Moderate southwest winds becoming light on Friday / Freezing levels at about 1500mSaturday: Cloudy with isolated flurries / Moderate west winds / Freezing level at 1500mSunday: Ridging will develop resulting in clearing skies and rising freezing levels

Avalanche Summary

Recent avalanches have been limited to loose wet sluff to size 1.5.

Snowpack Summary

North and Northeast aspects above 2000m continue to hold up to 20cm of dry snow, otherwise,  the surface condition is crusts. The carrying strength of the crusts vary depending on aspect and elevation as well as proximity to rocks, etc.... Generally speaking, the crusts have been going moist in the afternoon and then refreezing at night in all but the lowest terrain. Immediate lee features in the high alpine hold isolated softslabs that may still be reactive to rider triggering. Planar results have been observed in sheltered start zones. In some places outflow winds have reverse loaded pockets of the most recent storm snow onto the melt freeze surfaces of south facing slopes, creating small, reactive slabs in unusual places.In the upper snowpack (down 50-70cm) a significant melt-freeze crust lingers. Some facetting has been observed above and below this crust. At the same interface spotty surface hoar may linger on high, sheltered north facing terrain. There has been no recent stability test results on this layer.Cornices are huge and will continue to grow with the forecasted precipitation.

Problems

Wind Slabs

An icon showing Wind Slabs
New softslabs will likely build with forecasted precipitation.  Old windslabs linger and some previous reverse loading has occurred. Concern remains for step downs to isolated surface hoar on sheltered, high north facing slopes.
Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Avoid travelling in areas that have been reverse loaded by winds.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Cornices

An icon showing Cornices
Cornices are gigantic and may become weaker with additional wind and snow.
Pay attention to overhead hazards like cornices.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Apr 19th, 2013 2:00PM

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