Northwest Avalanche Center

Observation: Public

All Observations

Observation Details

Name:
Irene Henninger
Observation Date:
January 6, 2021
Submitted:
January 6, 2021
Zone or Region:
West Central
Activity:
Skiing/Snowboarding
Location:
Boulder Lake

Observed Avalanches

Did you observe any avalanches? 
Yes
Avalanche Type:
Dry Loose (Sluff)
Size:
Size 1: Relatively harmless to people
Elevation:
4500-6000ft
Aspect:
Comments:
Many dry loose avalanches ran naturally last night in new snow approx 15cm deep on steep slopes and all aspects. Today they were reactive to skier triggers on steep slopes and shady aspects.

Signs of Unstable Snow

None reported

Observations

We travelled to Boulder Lake then towards Boulder Benchmark, sticking to lower angle terrain and ridgelines on the way up, and returning via a similar path. (2700ft- 6000ft, W to N aspects).

Upper snowpack was wet until 4500ft but transitioned to powder above that (25cm F snow at surface). A pit at 5600ft, NW aspect had 380cm HS with 120cm of storm snow overlying the 12/21 interface. The storm snow was right side up, slowly increasing in hardness down to the P hard 12/21 layer. We found a failure 30cm down CT20 RP, ECTN14, which correlated with results from numerous hand pits as we travelled from 4500ft -6000ft.

Slight wind loading became evident above 5500ft. One of the few slab avalanches we found was a D2 at 6150ft on a NW aspect just below ridgeline. (Probably failed in the last 24 hours). We saw numerous very small loose wet avalanches midday as the skies cleared on upper elevation south aspects and all aspects below 4500ft. A natural loose dry avalanche cycle occurred at the end of last night's storm. Small loose dry avalanches were also reactive to skier triggers on steep slopes today.

Media

Slab avalanche at 6150ft on a NW aspect
Top 120cm of a snow pit at 5600ft on a NW aspect. Total snow height was 380cm.
The snowpack at 4200ft
Small pinwheels that came down during the day today at 4100ft, W aspect. Signs of old ones are present too.
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