Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 17, 2023
Submitted:
February 17, 2023
Observer:
NWAC Forecaster - Katie Warren and Andy Harrington
Zone or Region:
Snoqualmie Pass
Location:
Stampede Pass (2500-4200ft all aspects)

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced

Media/Attachments

Rollerballs were common on most steep slopes.
Pinwheels and rollerballs were a common theme of the day.
We traveled through quite a lot of terrain, using these quick hand pits to see how easily the new snow slides off the underlaying crusts. We found a favorable bond to the crust ↓40cm, and a weak bond with the most recent crust ↓5cm.
At times, you could see the sun through the clouds and snow.
We found great riding conditions in soft snow.

Advanced Information

Weather Summary

Cloud Cover:
Obscured
Temperature:
>30°F
Wind:
Light
New/Recent Snowfall:
HN24 was 5cm at 3800ft

We experienced moderate snowfall throughout the morning hours, around S1. Snow in the morning at all elevations had changed to rain below 3000ft by the early afternoon.
We were mostly in sheltered terrain. So we mainly saw light winds, but plenty of soft snow is still available to blow around.

Snowpack Observations

At about 4000ft, we found an HS of around 215cm and a generally right-side-up snowpack. The interface buried today consists of a thin, fragile melt-freeze crust with buried surface hoar below today's storm snow (5cm and counting). This week's storm snow rests on a melt-freeze crust and shows a favorable bond to this interface down about 40cm. The notable crusts in the snowpack are down 40cm, 145cm, and 170cm. We think these are the 1/12, MLK, and Christmas Crust, respectively, although it's quite different than other areas closer to Snoqualmie Pass proper.

It was a stormy day with temperatures hovering around freezing, steeper slopes were actively rollerballing, and pinwheels were prevalent. We observed no other signs of instability.

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