Avalanche Forecast

Issued: Apr 14th, 2015 9:21AM

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

swerner, Avalanche Canada

Northwest Inland.

Localized solar radiation, snow amounts and wind values may be higher than forecast. Use a conservative approach and watch for signs of instabilities like natural avalanche activity.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

The current weather pattern is more winteresque than it has been all season. Im beginning to feel seasonally confused. The lull before the storm is over, and the next one arrives in coastal and inland regions late tonight. Wednesday will be fairly stormy with precipitation amounts 5-15 mm. Ridgetop winds will be strong from the SW and freezing levels will hover near 900 m. On Thursday, up to 10 mm of precipitation is expected with continued strong west winds. Friday will be unsettled with light precipitation amounts and high solar in localized areas. Freezing levels will rise to 1000 m. A strong upper level ridge will set up over the province through the weekend and remain stationary until Tuesday bringing warm air and clear skies.

Avalanche Summary

No new avalanche observations have been reported. On Wednesday, touchy wind slabs and storm slabs are likely, especially in areas that receive higher snowfall amounts or localized solar radiation.

Snowpack Summary

Recent storm snow has likely formed touchy storm slabs. Strong westerly winds have redistributed this new snow and has formed wind slabs on leeward slopes and behind terrain features. The lack of bond between the new wind slabs and storm slabs over the older snow surfaces buried on April 9 th (surface hoar, crusts and facets) are the primary concern. The March 25th surface hoar / crust layer is reportedly unreactive, however; with the new load of wind and snow this should remain on your radar as it may re-awaken, initiating very-large and destructive avalanches. Large ripe cornices are also of concern and will be a problem with additional loading, especially when the sun and warm temperatures come back.

Problems

Wind Slabs

Strong winds have built wind slabs in lee terrain in the alpine and at treeline. They are especially touchy where they sit on buried facets, surface hoar and/ or crusts. Use caution and watch for reverse loaded slopes from changing winds.

Be cautious as you transition into wind affected terrain.>Pay attention to overhead hazards like cornices, especially if the sun is shining.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

Additional snow loading on the mid- March persistent weak layer could bring it back to life. Smaller storm slab avalanches may step down to this layer, initiating large and destructive avalanches.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar, facets and/ or a crust.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Apr 15th, 2015 2:00PM