Old Ski Bowl

The Old Ski Bowl weather station (7,600 feet) received about a foot of wet snow (3.25" SWE) from 6pm on February 23rd through 9pm on February 24th. Bunny Flat (6,900 feet) received less snow due to the high snow levels - about 7 inches were measured this morning. This significant load stressed the snowpack, as evidenced by the large slab avalanche off of Green Butte and the numerous wet loose slides on Gray Butte, all of which probably released late in the day on the 24th.

The Green Butte avalanche most likely failed on the February 14th graupel layer, which sits above the January drought crust and has been observed at many locations on Mount Shasta and at Castle Lake. Stability test feedback on this layer has been limited, but it is now suspected in two large natural avalanches (February 16th, February 24th). While unlikely, there remains a remote potential for human-triggered avalanches on this layer. 

Today, above-freezing temperatures and strong solar input initiated plentiful natural rollerballs and wet sluffs in the new, wet snow on steep, solar aspects, especially near rock outcroppings. 

On an east/southeast aspect at 8,100 feet, adjacent to the large slab avalanche on Green Butte, we recorded several non-propagating test results in the upper snowpack. The 2/14 graupel layer is buried over a meter deep, directly above a melt-freeze crust. Additional taps (>30) from the shoulder during an ECT produced propagation on this layer.  Another graupel layer was found about 12 inches above the 2/14 layer, but this layer did not produce any propagating results in snowpack tests. About 7 inches of recent, wet snow (settled) was on the snow surface.