Quick report
- Cracking
- widespread
- Collapsing
- widespread
This was a short walk in the dark to check-in with the snow and see how the current storm was affecting stability. I found an 8-10" thick slab of recent snow (from today's storm and a little bit earlier in the week) resting on 4" of very weak facets. These facets developed during the pause in precipitation and cold weather in the second half of November. Facets were well-developed and nearly cohesionless. All of this was resting on a stout crust from the mid-November drought and then upper elevation rains. It is not uncommon to have weak early season snow here, but the combination of slab + weak snow + stiff crust underneath was concerning. I experienced widespread cracking and collapsing involving the very weak facets that developed in late-November. I was impressed at just how widespread and reactive the cracking/collapsing was, given how relatively thin the slab currently is. This reactivity is a good harbinger of how these facets may behave with additional loading. I experienced this cracking/collapsing on both sheltered slopes and slopes with minor amounts of wind stiffening. Collapses frequently extended across entire open slopes and meadows, on the order of 100 feet or more from my location. I would have expected to trigger avalanches on steep, wind-loaded slopes. Hand pits clearly showed this weak structure as soon as I left the highway, around 8,200'. A snowpit dug at 8,600' on a N aspect produced ECTPV x 2 (failure while isolating the column) and ECTP 1 and 3 (pictured below). The mid-November facet interface has some complexity to it, thanks to small storms in the Thanksgiving/early December timeframe. I could see some surface hoar flakes down here, but didn't have to time to map out the distribution within the snowpack and across the terrain. Will be interesting to see how this looks in other places. All in all, a complex early season snowpack. Plenty of snow around for easy access from the highway (aspect dependent), but lots of sharks in the waters too.
Weather
- Cloud Cover
- obscured