Deep digging

Our goal for the day was to assess the deep persistent slab problem in the bulletin. We decided to start our investigation in the Face/Locomotive drainage area. We dug to the ground (310 cm) at upper treeline and found the layer of concern down about 250 cm. Where we were, it was a 15 cm thick melt-freeze crust with 1 mm rounding facets sporadically within it, i.e., not a uniform layer of facets. We performed a deep tap test with no result (DTN). It is only one data point and our plan is to try to expand on observations in the coming days. Otherwise, there was substantial wind effect from treeline to alpine elevations, but the surface remained soft enough for good riding conditions. Strong wind gusts were transporting more snow around, perhaps forming some new small slabs. We saw evidence of natural wind slab and cornice avalanche activity in Avalanche Alley and up high on the glaciers, all that likely occurred over 24 hours ago.

See photo for wind slabs, likely from 24 hrs ago or more.