Loose wet avalanches have been easy to trigger on steep slopes at treeline, they’re running far and accumulating mass as they slide.
Good group management will be a great tool for managing this hazard.
Up to 15 cm new snow is likely sitting on a crust on all but North aspects in the high Alpine. Expect pockets of wind slab in immediate lees as strong southwesterly winds in the wake of Monday’s storm have redistributed the new snow.
Up to 10 cm of new snow at treeline covers an isothermal upper snowpack. Where the late March crust has refrozen, it has made an excellent sliding surface for the 30 cm of moist snow that overlies it.
On Tues, a field team was able to easily trigger size 1 storm slabs on steep rolls at tree line and cut cornices triggering up to size 2 loose wet avalanches on steep faces. Loose snow avalanches were accumulating mass in the paths and running far.
A group exiting the Asulkan cabin Mon morning was able to easily trigger wet loose avalanches up to size 1.5 while descending the moraines.
Natural wet loose avalanche cycles, up to size 2, occurred on Sun and Mon in the highway corridor.
5-15cm of new snow at treeline & alpine. Earlier this week temps at treeline were above 0°C for over 48-hours, creating isothermal snow down 50-70cm.
In some locations the new snow has insulated the moist snow below it, preventing a crust from forming. In other locations the late March crust has refrozen creating an excellent sliding surface for the ~30 cm of moist (dry in alpine) snow on top.
Persistent weak layers linger in the mid-snowpack but will likely remain inactive.
Unsettled conditions continue Wednesday
Tonight cloudy, isolated flurries. Wind SW 20-30 km/h. Freezing Level (FZL) 1500m
Wed Mix of sun/cloud, isolated flurries. Alpine high -3°C. Wind SW 20. FZL 1900m
Thu Flurries (8 cm). Alp high 0. Wind SW 25, gusting 70. FZL 2200m
Fri Cloudy with sunny periods. Alp high -5. Wind SW 20-40. FZL 1500m
