Touchy Wind Slabs on Powderhouse Peak

20 to 30 cm (8 to 12 inches) of new cold snow existed on top of yesterday's rain-soaked snow. Observations, snowpit data, and ski cuts on test slopes in near and below treeline, non-wind affected terrain showed a right-side-up snowpack with good bonding between these layers as well as between yesterday's moist snow and the older snow surface.  The 20 to 30 cm of snow that accumulated last night and today did not exhibit slab characteristics in near and below treeline sheltered areas. Ski cuts did cause some minor sluffing in this cold new snow on steep below treeline test slopes. Snowpit tests and observations from the same area as the unstable results on March 11, showed significant rounding and moisture in the old persistent weak layer and did not yield unstable results today.

In near and above treeline terrain exposed to the winds, fragile wind slabs had formed on wind-loaded test slopes. Ski kicks and ski cuts on wind-loaded test slopes easily caused these wind slabs to fail and caused shooting cracks up to 5 to 6 m (15 to 20 ft.) long. These wind slabs only involved last night's snow and did not extend into the yesterday's moist wet snow. These wind slabs measured up to 30 to 40 cm (12 to 16 in.) in depth. We also experienced 2 whumpfs while traveling on a ridgeline as a nearby wind slab collapsed but did not slide. Investigating this area showed the wind slab resting on top of softer snow but did not reveal any signs of a persistent weak layer.