Storm slabs may be reactive to human triggering, especially at upper elevations.
Careful snowpack evaluation, cautious route-finding, and conservative decision-making are essential.
This layer remains a concern on north-facing, alpine terrain where the snowpack depth is variable. This layer may become more reactive with the added stress of new snow and wind.
Storm slabs may be reactive to human triggering, especially on leeward slopes that have deeper deposits of wind loaded snow. Back off if you find signs of instability like whumpfing, shooting cracks, or recent avalanches.
On Tuesday, sluffing from the intermittent solar input occurred in steep terrain. Continued evidence of a widespread cycle to size 2 from last weekend's storm was reported. Some of the avalanches ran on the February persistent weak layer down 100 + cm.
Storm slabs may be reactive to human triggers on Wednesday, especially at treeline and in the alpine on leeward slopes that have seen more wind loaded snow.
Up to 65 cm of storm snow sits above a crust on all aspects except on high, north-facing alpine terrain, where the new snow sits above an interface of dry snow. In some areas, beneath the new snow sits surface hoar on the crust. This crust/ surface hoar formed in early March. Moderate to strong southwest winds have redistributed storm snow into deeper pockets on lee slopes at the ridgeline.
A persistent layer of facets and surface hoar which formed in February have been found 80 to 140 cm down, and a layer of facets and surface hoar from late January can be found down to 120 to 180 cm. Recent snowpack testing shows a sudden planar result on surface hoar down 145 cm.
Wednesday Night
Cloudy with 5 to 10 cm. 10 to 45 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1000 m.
Thursday
Cloudy with snow 10 to 20 cm. HIgher amounts possible for Allison Pass area. 15 to 40 km/h southeast ridgetop wind. Treeline temperature -4 °C. Freezing level 1000 m.
Friday
Cloudy with sunny periods. 10 to 15 km/h southeast ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.
Saturday
Cloudy with 3 to 7 cm of snow. 15 to 55 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1200 m.
More details can be found in the Mountain Weather Forecast.
