Poor snow surface refreeze on Donner Summit.

Once stepping off of the previously packed roads in the Castle Peak/Andesite Ridge area, it was readily apparent that a very weak and superficial snow surface refreeze occurred in the area last night. A 1 to 2 cm thick melt freeze crust existed on the snow surface during the early morning hours. By 9 am, this was a breakable crust in shaded areas and was fully melted in wind protected areas of full sun exposure. In sunny areas where the snow surface was exposed to the east winds, snow surface melt was slower, but boot penetration through the crust down 15 cm into the snowpack was observed. At that time ski conditions on open, sun exposed SE aspects between 7,600' and 7,200' ranged from supportable, to semi supportable, to unsupportable. The widespread upper snowpack structure of wet snow on top of colder, dry remnant storm snow was observed in this area on SE-S-SW aspects traveled.

Photo 1: 1 cm thick surface melt freeze crust on open, E wind exposed SE aspect at 7,400'. 1 Finger+ hardness.

Photo 2: Breakable crust in shaded areas.

Photo 3: Snow surface crust fully melted in sun exposed, wind protected area within 100' of shaded breakable crust area.

Photo 4: Boot pen of 15 cm on open wind exposed SE aspect at 7,500' (noted lat/long).