Avalanche Forecast

Good

Wednesday: Flurries, with only light accumulations, or none at all. Starting cold, but temperatures warming in the afternoon. In the norther areas, freezing levels could climb as high as 2000 m, interestingly, cooler in the south. Ridgetop winds 40-60 km/h from the southwest.  Thursday: Flurries. Freezing levels 1500 m in the south of the region, 2000 m in the north. Ridgetop winds around 40 km/h from the southwest.  Friday: A storm with uncertain precipitation amounts looks likely. At present models indicate around 5 cm for this region, but this could change. Freezing levels look very high - around 2500 m. Strong southwest winds are likely.

The most recent storm produced numerous avalanches. While most of these were relatively small (size 1.5), there were at least two notable exceptions. One natural avalanche pulled out a size 3 slab on a north aspect in alpine terrain above 2100 m, releasing around 70 cm deep on the mid-January surface hoar layer. Another was reported as a size 2.5 remote-triggered avalanche triggered from 300 m away. This avalanche occurred on a southeast aspect at 1900 m, with a crown depth of 80 cm. It initiated on the mid-January surface hoar layer and stepped down to the mid-December surface hoar/crust layer.

Between 30 and 50cm of new snow has fallen since Friday night, and has been distributed by strong winds into deeper, more cohesive deposits in higher wind-exposed terrain. The new snow overlies a weak layer that comprises 5-15 mm surface hoar that lies above a crust in many areas, especially on south-facing slopes. This "mid-January" weak layer is widespread. It has been the main focus for recent avalanche activity, and is also consistently producing easy "pop" type failures in snowpack tests.The still problematic mid-December surface hoar/crust layer is now buried anywhere from 60 to 110cm below the surface and continues to produce clean shears at and below treeline. Avalanches were reported to have stepped down to this layer during and after the most recent storm cycle. Although it has become less likely to trigger, I'd continue to treat this layer with respect and suspicion, particularly in the 1700-1900 m elevation band, as a release on this layer would result in very high consequences.