Freezing levels spike on Sunday which will increase the likelihood of large natural and human triggered avalanches. Avoid slopes with overhead exposure where falling cornices could trigger large avalanches.
Summary
Confidence
High
Weather Forecast
Freezing levels are forecasted to spike to as high as 2700m on Sunday with cloudy skies and possible flurries overnight. Monday looks cloudy with lowering freezing levels. Tuesday should be clear and cool with freezing levels dropping sharply. Light to moderate southwesterly winds until Monday evening when they calm down.
Avalanche Summary
On Friday, several large cornice failures triggered slab avalanches up to size 2.5. Additionally, there was a natural size 3 slab avalanche on a southeast aspect at 2500m. This tells us that the late February weak layer is still alive and well even though it may be difficult to trigger in most areas. Small loose wet avalanches and failing cornices triggering slab avalanches on the late February layer would be on the forefront of my mind as I travel through the mountains this weekend.
Snowpack Summary
At ridgetop, cornices are huge and could become increasingly touchy with rising freezing levels and solar radiation. Old wind slabs still linger on lee features at treeline and in the alpine and may become more reactive with solar radiation. 60-110cm below the surface you'll find a persistent weak layer comprised of surface hoar, facets and/or a thick crust. This layer seems variably reactive. In other words, it's still reactive to human triggers in some places while in other spots it's really tough to trigger, and there's not much of a reliable pattern telling us what exact aspects are most suspect. I'd continue to be suspicious of steep, unsupported features at treeline and in the alpine as this layer has the potential to produce large avalanches. Below this interface, the snowpack is generally strong and well-settled.
jsmith,
Avalanche Canada
