Observation: Public
Observation Details
Name:
Enji CooperObservation Date:
February 28, 2021Submitted:
March 1, 2021Zone or Region:
West SouthActivity:
XC Skiing/SnowshoeingLocation:
High HutSigns of Unstable Snow
Observations
Time: 10:30
Conditions: OVC (overcast)
Location: Lower Sno-Park South Tahoma Trails (46.7063, -121.9934)
Snow conditions:
- wet loose/unconsolidated (sprinkling at lower elevations).
- No visible stability or instability.
======
Time: 11:30
Conditions: OVC
Location: Past Upper Sno-Park South Tahoma Trails (46.6928, -122.0116)
Snow conditions:
- wet loose/unconsolidated (sprinkling at lower elevations).
- larger volume snowpack.
- wet loose conditions observed with pinwheels/rollerballs.
======
Time: 12:30
Conditions: X (obscured)
Location: 46.6866, -122.0256 (Ben Jones loop cut-off)
Snow conditions:
- heavy, wet storm snow.
- snowshoes sank around 1' down off groomed track.
======
Time: 12:45
Conditions: X ; RA/PP (rain; sprinkling)
Location: High Hut/Anderson Lake road junction (46.6844, -122.0338)
Snow conditions:
- storm/wind fetch snow.
- snowshoes sank ~1' down off groomed trail.
- ~2' broken crowns on north/eastern side of ridge.
======
Time: 14:00
Conditions: X ; RA/PP (rain; sprinkling)
Location: High Hut
Snow Conditions:
- undisturbed snowpack off trail compressed ~3" with snowshoes.
- wind loaded on east side of ridge.
Comments:
Dug basic pit to discuss overall motivation and demonstrate relative pressure test, practice digging pit, demo quick and dirty isolated column test, etc.
Due to time constraints and location, pit wasn't cleanly dug, but the general observations seemed to be as follows:
* Location: High Hut: 46.6966, -122.0260
* Snowpack: ~144cm to base.
Relative pressure test:
* 144-136cm: new rain crust (fist)
* 136-130cm: storm snow (fist)
* 122-119cm: finger+
* 119-109cm: finger
* 109-107cm: hard rain crust (ice; could not disturb)
* 107-78cm: 4 finger
* 78cm: finger+
ICT (isolated column test):
* CTM (moderate) /PC (progressive compression) (Q2) at 18 loading steps at 136cm.
** Non-planar break
======
Time: 16:00
Conditions: BKN (broken skies)
Location: Lower Sno-Park South Tahoma Trails (46.7063, -121.9934)
Comments:
* No new snowpack instabilities observed.
* Temperature had warmed since start (approximately 3-5 degrees F warmer).
Media
Advanced Observations
Observed Avalanche Problem #1:
Wind SlabComments:
Noted wind loading (including some older broken crowns from what appeared to be storm snow) on north and east aspects of ridge for road up to High Hut.The broken crowns looked like they were D1 (3") in size.
High winds earlier in the season likely broke smaller trees in area; originally thought it was caused by avalanches, but that doesn't make sense given other evidence in area.
Observed Avalanche Problem #2:
Wet LooseComments:
Noted pinwheels (small diameter, e.g., 3" and large, e.g., 2' diameter) and small pinwheels along road around 3.2k' and higher.Didn't observe wet loose conditions past 4k'.