Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 21, 2022
Submitted:
February 21, 2022
Observer:
NWAC Forecaster - Irene Henninger
Zone or Region:
West Central
Location:
Deer Creek (S,1600-4500ft. All aspects at 5000ft)

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

The crust which formed on the surface of south aspects when skies became cloudy.
Impressive elasticity of the new snow.
Small very low density wind lips features were present by 4000ft in the trees. This was the only cracking I got.
In this pit there were obvious weaknesses in the Valentine's crust/combo layer, whereas the late Jan crust was well bonded.
This was the only pit where the Valentine's Crust was one thick layer rather than a crust sandwich. The late Jan Crust however, had an obvious weak layer just beneath the uppermost crust layer, unlike the other pits. Results were still ECTX/CTN.

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Temperature:
32°F
Wind:
Calm
New/Recent Snowfall:
45cm at 5000ft (2/19-20)

The day started with clear skies and small patches of valley fog. The VF continued growing throughout the day, until I was nearly completely surrounded by obscured skies from 3pm- with the occasional blue patch visible. Short wave radiation was intense while the sun was out, but it cooled quickly as sky cover increased.

I saw many small loose snow avalanches which had already run. Some were dry and on north and west-facing slopes while others were wet on east and south-facing slopes. All the old avalanches I saw were mainly limited to the top 6 inches of snow. Views were obscured so sighting any possible larger avalanches on nearby peaks was unsuccessful.

Snowpack Observations

Recent snowfall (2/19-20) started at around 2000ft and was a foot deep by 3000ft. The new storm snow was shallow in moderately treed areas up to 5000ft, with only about 4-6" over a hard crust. Snow was dry until I encountered south-facing meadows at 4500ft at noon, where moist snow and icing skins began. In open areas at 5000ft the storm snow was about 18 inches deep. Fist to 4Finger to 1Finger above the Valentine's Day Crust. On southerly aspects the snow rapidly consolidated midday and was moist down to the crust.

I dug several pits at 5000ft, where the obvious layers were the Valentine's crust layers (foot and a half down) and then the Late Jan crust about a foot below that. I got mixed results, with an ECTP25 on a Valentine's Crust sandwich in one pit, but ECTX's in two other pits. In 2 of the 3 pits the Late Jan crust was well bonded to nearby layers, except one pit where I still found the weak structure between two crusts but it was uncreactive in tests.

Sun was intense midday- trees were shedding and forming dripping icicles. South facing snow surfaces were moist, yet, by 3pm skies were ominously dark and a 2cm crust had frozen on south faces at the surface. Lower elevation areas where I'd previously traveled through dry low density snow were now all moist.

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