Old Ski Bowl and Upper Green Butte Ridge

The objective of today was to assess new snow instabilities on the south side of Mount Shasta through all forecasted elevation bands. As it stands, a wide range of variability exists in the current snow conditions. Below treeline, the snowpack remains very thin. The recent storm was warm enough to mostly provide rain to this elevation band. While no real avalanche hazard was found in this zone, natural hazards like trees and rocks are abundant. Near treeline, multiple wet-loose avalanches were found accompanying the 9 inches of new snow. This new snow is relatively dense and right side up. Above treeline, new snow totals were closer to 12 inches, and the snow was cold, dry, and relatively low density. These higher zones also had a different avalanche problem than at lower elevations. Fat, wind loaded slopes were found on east, and west aspects, sometimes lower on the slope than expected.

Upon descent from Old Ski Bowl, near treeline terrain had already begun to freeze up, and forming a punchable solar crust at the surface. 

There were two different significant signs of instability observed today: 1. A pronounced wet-loose avalanche problem in near treeline terrain, on south, east, and west aspects. Multiple natural avalanches were observed, having occurred in the last 12 hours. All were around D1. 2. Small shooting cracks were found on wind loaded slopes above treeline. These wind loaded slopes were specific to east and west aspects, and restricted to above treeline terrain.

A pit was dug on a southeast aspect in Old Ski Bowl, at around 8,600 feet. The 12 inches of new snow was found on top of a knife-hard crust with wet old snow below. The rest of the snowpack was a series of old snow and crusts since November. Extended column tests showed some minor failure within slight density changes of the new snow, and a little larger failure on the wet snow from 12/29.  None of these failures propagated across the column. In all, there was nothing to be alarmed about.

Overall, new snow totals ranged from 9 inches at around 7,000 feet, to 12 inches at 8,600 feet and above. This snow fell onto a crust that had developed yesterday as temperatures cooled. The cohesion of new to old snow varied on elevation. Below and near treeline, the new snow appeared dry but heavy, sticking strong to the crust below. Above treeline and at higher elevations, this new snow appeared to be relatively cold, dry, and lower density. At these higher elevations, the crust below was much more firm and supportable, but lacked the cohesion to the new snow.