Avalanche Forecast

Issued: Apr 14th, 2013 10:10AM

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

mpeter, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

Monday: Expect a mix of sun and cloud, with alpine temperatures reaching -6 and freezing levels climbing to 1300m. Winds should be light to moderate from the northeast. Intense convective snowshowers are possible in the afternoon.Tuesday: Mixed skies again with alpine temperatures of -5 and freezing levels around 1400m. Winds remain light to moderate from the northeast.Wednesday: Expect clouds to build through the day with alpine temperatures reaching -4 and winds turning southwesterly.

Avalanche Summary

Both rider and remote triggered events have been reported in high (2400-2700m) north and northeast facing slopes up to size 2.0, all associated with preserved surface hoar.

Snowpack Summary

Convective snowshowers have given up to 45cm of new snow at higher elevations accompanied by light to locally moderate south/southwest winds creating new windslabs in lee locations at treeline and in the alpine. The interface of the new snow is predominantly crusts (sun, wind, meltfreeze) and the bonds are poor in some locations.The previous storm (Wednesday) was accompanied by moderate to strong south/southwest winds which left variable snow distribution in exposed areas near ridgetop with dense wind slabs in lee and cross-loaded features. These slabs are now buried, but may still be reactive to heavy triggers or in specific locations. Up to 75cm below the surface you will likely find a melt-freeze crust from previous sunny weather. At the same interface, spotty surface hoar is still being reported (up to 20mm!) in some high, north facing slopes. Where the surface hoar is present, consistent sudden results have been observed.Cornices are huge and have grown new tabs under the current conditions.

Problems

Cornices

Recent snow and wind has added mass to existing cornices.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 6

Wind Slabs

New windslabs have formed in immediate lee locations and the bonds with the underlying crusts may be suspect. In specific terrain avalanches have been stepping down to a persistent surface hoar layer buried last week.

Dig down to find and test weak layers before committing to a line.>Be cautious as you transition into wind affected terrain.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Loose Wet

The surface snow will destabilize on south and west facing slopes in the afternoons if the sun is out

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 15th, 2013 2:00PM