Observation: NWAC Forecaster

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Weather Summary

Very cold temperatures at lower elevations with warm air filtering in at higher elevations. We observed some very warm-feeling westerly breezes above 5500 ft. Snowfall rates picked up during the afternoon hours.

Avalanche Observation Comments:

Intentionally triggered a D1 soft slab on a small wind loaded slope with a stomp. Crown depths were 8 -12 inches deep and likely failing on 12/18 interface. NE aspect at 5900 ft.

Snowpack Observations

On Friday my partner and I traveled into the McCue Ridge area, east of the Chiwaukum Mountains. Thanks to Alpine Lakes High Camp for the bump up to camp! Our goal was to take a look at the current snowpack in this lesser known area and to see how the forecasted weather pattern will influence the current snowpack structure.

Throughout our tour we traveled on multiple aspects along McCue Ridge at approximately 5500 ft. Generally we found 30-40 cm of low density snow on top of the 12/18 interface. In more sheltered areas the HS ranged from 90 cm on south aspects to 120 cm on more north facing slopes.

On South aspects we observed a shallow snowpack and a stout crust beneath the new snow. On these aspects we did observe some weak, faceted snow sitting on a crust.

On more northerly aspects, we observed a deeper, yet also a weak snowpack structure. The weak faceted snow buried on 12/18 was much more notable on these aspects. I was even able to intentionally trigger a small D1 soft slab in a wind loaded pocket that failed approximately 8-12 inches deep on these weak faceted grains.

At 5800 ft on a NE aspect I dug a test profile to investigate older interfaces (12/8 & 11/22). At this location I did not find any buried surface hoar associated with the 12/8, however I still located rounding-facets adjacent to the late November crusts. The late November crust interface was 70 cm deep in this location. You can find weak snow above this crust, but also weaker snow below (4F hard).

Overall, the snow sitting on top of the 12/18 interface remained low density and lacking slab-like characteristics in most areas we traveled, except for wind drifted areas near ridgetop. These wind loaded areas were reactive and easily failed on this weak, faceted snow.