Warm temperatures in alpine areas could cause large, unexpected avalanches, especially on south-facing slopes.
Summary
Confidence
Fair - Freezing levels are uncertain
Weather Forecast
Saturday and Sunday: Dry or very light flurries, with alpine temperatures around -2C. Winds expected to be light southwesterly rising to moderate southeasterly. Monday: Clear with sunny spells. Temperatures below freezing at low elevations but alpine areas may see inversion conditions that will elevate temperatures to near zero.
Avalanche Summary
On Friday, slab avalanches up to size 3.5 were reported in response initially to rain and then during the day to intense solar radiation. On Thursday, numerous large (up to size 3) slab avalanches were reported out of lee terrain (SW predominantly) along Bear Pass during the warming period as the snow turned to rain. Lower elevations were especially active.
Snowpack Summary
Total snowpack depths pushing 5m at treeline are at new record levels for this time of year. Recent warm temperatures helped settle storm snow into a touchy surface slab at lower elevations. Other weaknesses can be found within the upper snowpack and the Jan. 20th facets down around 150cm. These create the potential for large step-down avalanches, but things seem to be settling rapidly. Strong winds associated with recent storms means large weak wind slabs and cornices on lee and cross-loaded terrain. Most snowpack concerns are limited to the surface layers. However, large triggers such as cornice falls and smaller avalanches stepping-down could affect deeper weaknesses.
jfloyer,
Avalanche Canada
