Small wind slabs in isolated locations on steep terrain may remain reactive to human triggers.
The crust formed by the rain event last week has created a significant falling hazard in steep terrain.
Small wind slabs in isolated locations on steep terrain may remain reactive to human triggers.
Cornices overhead are a primary concern during sunny, warm, or windy conditions. Cornice failures may trigger large persistent slab avalanches that would otherwise be difficult to trigger.
TUESDAY NIGHT: Increasing cloudiness / Strong, northwest wind / Low of -6 / Freezing level valley bottom.
WEDNESDAY: Cloudy with isolated flurries; 0-3 cm, and another 3-5 cm overnight / Extreme, west wind / High of -1 / Freezing level 1000 m.
THURSDAY: Cloudy with flurries; 3-5 cm / Extreme, northwest wind / High of 1 / Freezing level 1200 m.
FRIDAY: Cloudy with flurries; 5-10 cm / Strong, west wind / High of 1 / Freezing level 1200 m.
Several natural size 2 cornice failures were reported on Monday. None of them triggered slab avalanches on the slopes below.
5-10 cm of wind-pressed snow overlies a thick (10-15 cm) rain crust that extends to mountain tops. This crust has created challenging travel conditions and a "slide-for-life" hazard on steep slopes.
Small wind slabs may be found on lee features in the alpine.
The weak layers in the snowpack (such as the crust or surface hoar layers down around 100 cm) are unlikely to human trigger in areas where a hard surface crust is present. If the surface crust is warmed up and breaks down, triggering persistent slab avalanches becomes more likely.
However, cornices overhead are a primary concern during sunny, warm, or windy conditions. Cornice failures may trigger very large persistent slab avalanches that would otherwise be difficult to human trigger.
