Whoop Um Up
Quick report
Observations were in line with the forecast for Banner Summit (closest forecast area): "Today's storm will form slabs on...surface hoar," and, "While less likely, avalanches may fail in weak snow near the ground." Driving back down to Idaho City at approximately 1500, we saw roller balls and pinwheels on steep slopes.
Weather
- Air Temp
- 33.8
- Cloud Cover
- overcast
- Wind Loading
- none
- Recent Snowfall
- 19
Temperatures warmed throughout the day. Over the course of about an hour at the snow pit, the temperature at this specific location was 1C then rose to 2C, and continuing rising. Precipitation earlier in the day was snow (S1), then stopped for approximately 45 min, then became mixed rain and snow (S-1) for approximately 30 min, then stopped again. There was no wind.
Snowpack
Generally, most of the snow profile was faceted snow separated by a melt-freeze crust, overlain by surface hoar that was then buried by the new snow, which was heavy and wet. 0-19 cm (F): New snow and decomposing storm snow, heavy and wet (-1C) 19-28 cm (F): Buried pre-storm surface hoar, with crystals up to 16 mm (-1.5C) 28-37 cm (4F): Faceted snow (-1.5C) 37-44 cm (P): Melt-freeze crust (-1.5C) 44-61 cm (F): Faceted snow (-1 to -0.5C at ground) * A CT test showed progressive compression (PC) beginning at CT4 down 19 cm (compressing the buried surface hoar), then CT24 SP down 44 cm (interface of the basal facets and melt-freeze crust). * An ECT test showed ECTN2 down 19 cm and ECTN18 down 28 cm (both only right under the shovel) * A PST test showed PST 21/100 SF down on the buried surface hoar. Continuing the PST showed PST 40/100 END down on the buried surface hoar.