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New Year, New Week Layer?
Location Name:
WMR Backcountry
Observation date:
Monday, December 30, 2019 - 12:30
Is this an Avalanche Observation:
No
Observation made by:
Public
Tabs
Quick Observation
Seeking blower from last week atop a firm crust layer, we traveled into the Southern Whitefish Range from the resort. We were also interested in learning more about early-season crusts, as well as the prevalence of surface hoar.
The morning began with an inversion, and we started noticing newly formed surface hoar once we broke through the cloud at about 6,500 feet.
To check out the early season crust lineup, we dug a pit on the shoulder of Peak 6895, at 6,720 feet, about 50 feet below the ridge, on a 37 degree S/SE slope. The pack depth was 129 cm. We measured ~1 cm of surface hoar on top of 14 cm of unconsolidated snow. That later of fluff was sitting on a melt-freeze crust about 8 cm thick. Below this fat crust, there was a layer cake of semi-homogeneous early-season crusts. We conducted an ECT and had no failure. The snow on top of the melt-freeze crust is still pretty unconsolidated—while skiing, we did experience small sluffs as has been reported elsewhere in the region.
After the ECT, we did hasty shovel shear test, and got the upper 90cm of the pack to pop out on a planar interface.
Overall, skiing was not shabby where the top crust was smooth, and we’re curious to see what happens to the snow on top of the melt-freeze crust in the coming days and weeks. Hopefully the new surface hoar doesn't become the next "fill-in-the-blank-holiday" weak layer.
Snowpack, Avalanche, Weather Images:
Travel Details
Region:
Whitefish Range - Southern (south of Coal Creek)
Activity:
Skiing
Snowpack Details
Snowpack and Weather Details:
Terrain
Elevation of observation:
Above 6500 ft
Aspect(s) of observation:
SE
S
SW
Persistent Weak Layers:
Surface Hoar
Facets or Faceted Crust
On the surface
Buried
Total Snow Depth:
129
Wind Speed:
Calm (No air motion)
Sky Cover:
Partly Cloudy (SCT)
