Prayer Flags

Snow quality was very good but reactive. 45+ cm storm slab at treeline perched on rain crust from last week. Snow that was unsupported from below was extremely likely to shed off of rain crust. Any slopes that had been undercut by ski tracks, lacking support from snow below, were very easily triggered. Surface slough was slow moving until movement reached the rain crust, at which high volumes of snow were able to travel quickly. The second skier was triggering 1m wide blocks running along exposed raincrust approx. 50m downslope. The third skier on the slope triggered a size 1.5 avalanche that propagated approximately 8m across, with approximately 30 cm crown and a runout of 10-15m.

Three skiers rode the same slope, W-NW aspect 35-38° (Prayer Flags). The first skier experienced sloughing of surface snow, with some movement of snow down to the buried rain crust. Second skier was triggering larger blocks of snow that were now unsupported and quickly moved down slope along the rain crust while collecting other debris and blocks. Third skier triggered a slab avalanche that propagated approximately 7m across the slope, with a 25-40cm crown and a runout of 15-20m (partially stopped by a tree downslope). Snow movement seemed dependent on a lack of support from snow below, and exposure of raincrust.

Storm snow is well consolidated as a slab but perched on hard rain crust from last week. We did not dig a proper snow pit, however 8 hand taps on a test block triggered 40cm release on the rain crust.