Avalanche Forecast

Issued: Apr 14th, 2015 9:27AM

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

swerner, Avalanche Canada

Northwest Coastal.

Tricky winter conditions exist at higher elevations. Localized solar radiation, snow amounts and wind values may be higher than forecast. Avoid avalanche terrain during periods of heavy loading by snow, rain and wind.

Summary

Confidence

Fair - 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 15-25 mm. Ridgetop winds will be strong from the SW and freezing levels will hover near 1100 m. On Thursday, 5-10 mm of precipitation is expected with continued strong west winds and freezing levels near 1000 m. The next bulk of precipitation comes Friday and hits mainly the coastal areas (around Terrace and west) with precipitation amounts up to 25 mm. Ridgetop winds will be moderate from the SW and freezing levels will rise to 1500 m. A strong upper level ridge looks to set up over the province through the weekend and remain stationary until Tuesday bringing warm air and clear, sunny skies.

Avalanche Summary

On Monday, explosive control showed numerous storm slab and wind slab avalanches up to size 2. These were primarily from N-NW aspects above 1300 m. With continued snow, rain, and strong winds natural avalanches and human triggered avalanches will likely continue on Wednesday. Lower elevations which have become rain soaked may see natural loose wet avalanches.

Snowpack Summary

At upper elevations 25- 40 cm of recent storm snow has blanketed the region. The new snow has been redistributed by strong south-west winds into wind slabs on leeward slopes and terrain features. With recent changing winds from the NE, you may find some reverse loaded pockets in unsuspecting places. 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) is 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. Moist- rain soaked snow exists at lower elevations.

Problems

Storm Slabs

Storm slabs are touchy, especially where they sit on a buried facet, surface hoar and/ or crust interface. Strong winds have built wind slabs on leeward slopes and behind terrain features. Use caution and watch for reverse loaded slopes.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

Additional storm 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, destructive avalanches.

Use conservative route selection, stick to moderate angled terrain with low consequence.>Be aware of the potential for large avalanches due to the presence of buried surface hoar and facets on a crust.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

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