Observation: Public

Observation Details

Signs of Unstable Snow

Observations

Attempted to ski Mt Mastiff, off amd on snow showers with some rays of sun here or there but stayed mostly cloudy all day, no wind.

On a ridge at 5900ft found minimal wind effect except small drifts on west aspects of a ridge from previous E winds. General set up was ~10cm of slightly more dense snow over recent surface hoar, and 5cm of small facets over a solid 12/9 melt freeze crust, but no slab yet. Buried surface hoar nearly everywhere I looked, some 5-10cm above the crust. Small facets were consistently between the surface hoar and crust. On south aspects exposed to the sun there is a buried, thin sun crust with surface hoar above, weak snow below.

Skinning up the E slopes of Mastiff we started finding a bit more slab, more like 20cm over the crust and some slightly stiffer snow, likely from previous winds. At 6.2k started getting consistent long cracking and even a few large whumphs. One boomed and was perhaps a 30m radius out onto the open slope. It was surprising to see how reactive and far the fractures were traveling with only 20cm of snow over the weak layer.

We identified the failing layer as 1-1.5mm facets just above the crust, which was very smooth as well. Tricky to say if the surface hoar was part of the equation, might be. Went turned around at 6.4K knowing we could remotely trigger a slide above us with these conditions.