Avalanche Forecast

Poor - Due to the number and quality of field observations

The high pressure ridge continues to dominate the coastal regions. Strong alpine temperature inversions will be prominent and freezing levels will be rising to 2400 m. Moderate to strong outflow winds will prevail in coastal valleys especially in the overnight and early morning. Valley cloud may accompany the strengthening temperature inversion. By Sunday the weather pattern may see a change, however; timing and intensity of the next Pacific system is hard to pin point due to disagreement between the Canadian model and the GFS.

On Tuesday, a size 1 skier triggered slab was reported from an east aspect @ 1900 m as well as numerous natural wind slab avalanches from southerly aspects up to size 1.5. I suspect these stiff wind slabs may remain sensitive to rider triggers and as the warm air aloft invades the region watch for obvious clues like natural avalanche activity and moist/ wet snow surfaces, especially on southerly slopes. Smaller avalanches may also trigger deeper layers beneath the the surface, initiating larger avalanches.

Monday's 20 cm of storm snow has seen some serious effects from the recent winds and cold temps. Northerly winds have likely built stiff wind slabs on southerly slopes and stripped snow from exposed aspects. These wind slabs may have a poor bond to the old surfaces that comprise of surface hoar, crusts (potentially up to 2100 m) and some dry facetted snow above that. Strengthening temperature inversions at upper elevations may start to deteriorate the upper snowpack, especially on southerly aspects. Watch for obvious signs of instability like moist and/or wet snow surfaces and snow balling. Where the buried crust is thick, avalanches failing on deeper layers beneath have become much less likely. My uncertainty lies at higher elevations where the buried crust doesnt exist and deeper persistent weak layers may. Reports indicate that these shears are resistant in the moderate to hard range with sudden fracture characteristics. I'd remain extra cautious as they may be sensitive to rider triggering.