Quick report
I went for a day-off walk in the mountains above Lake McDonald to enjoy the sunshine, admire the views, and determine how much snow fell during the 12/7-12/8 storm. The Flattop SNOTEL (6300 feet) reported 1.6 inches of SWE and 13 inches of settled new snow during this event, and we were interested in comparing how the mountains around Lk McDonald fared.
- At 6300 feet, 3-4 inches of recent snow rested on a 1 cm melt-freeze crust formed during warming and rain over the weekend. In multiple hand pits, we noted that this rain destroyed most, if not all, of the surface hoar layer. This crust extends to at least 6800 feet.
- At 7400 feet, eight inches of recent snow rested on a surface hoar layer formed during the 12/2-12/6 high pressure.
- Great visibility allowed for views of the surrounding terrain. No recent avalanche activity was noted.
- There was a surprising lack of wind-affected surface snow.
- Strong solar input melted rime and snow off trees up to 7100 feet throughout the day. The snow surface became moist on sunny aspects.
- The snowpack below 6000 feet is thin and peppered with downfall.
Weather
- Air Temp
- 26
- Cloud Cover
- clear
- Wind Loading
- none
- Rain Elevation
- 2000
- Recent Snowfall
- 4
- Snow Avail For Transport
- small smounts
A stratus cloud deck sat between 4500-5500 feet throughout the day. Above this was bountiful sunshine until high clouds moved in from the west around 1500.
Snowpack
The snowpack depth at 6300 feet was 24 inches compared to Flattop's 38 inches.
At 7400' on a slightly wind-loaded slope, the depth was 40 inches. Compression Tests showed failure on the surface hoar layer CT 11, CT12. The surface slab was soft at our snowpit and resulted in ECTN 12.