Large gullies ran mid-storm 1/31 or early 2/1 on the southern flank of Lichtenberg.
Signs of Unstable Snow
Did you see shooting cracks?
Did you experience collapsing or whumpfing?
Calm day giving way to breezy conditions and light to moderate snow. We had a dig at 5000' on a southwest slope where there was evidence of some wind loading. PST50 end on facets over the 1/30 crust and high single digit CTs on the density change. CTs in mid teens on preserved stellars. ECTN16 on stellars.
Most obvious red flags were around 3300-3500' in flat valley bottoms that had stayed cold during the inversion, where we had a dozen small to medium collapses. We saw much old wet loose debris on steep features 4000-5000' on Lichtenberg mountain, but didn't notice any crowns from recent slab avalanches.
We stayed below ridgeline all day and avoided northerly aspects given that prior travel showed more weak snow on polar aspects. It will be interesting to see if the incoming wind/precip and subtle warm-up activate the interface we tested on other aspects and ATL.
Observed Avalanche Problem #1:
A variety of weak grains underlay the most recent storm: facets, surface hoar, freezing rain, wet grains. The facets and surface hoar were wet in several hand pits to 5k' as the weather warmed before the storm.
Observed Avalanche Problem #2:
Within the recent storm (HST to 50cm), there are several interfaces, including preserved, iced stellars 25-30cm down and a density change mid-storm interface 15cm down.