Observation: NWAC Forecaster

All Observations

Basic Information

Observation Details

Observation Date:
February 1, 2023
Submitted:
February 1, 2023
Observer:
NWAC Forecaster - Matt Primomo
Zone or Region:
East Central
Location:
NW side Cannon Mtn

Signs of Unstable Snow

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

Media/Attachments

Quick profile on a N aspect at 4300ft. HS was 135cm. 18cm of faceting snow over the weakening MLK crust (with very weak facets beneath), 65cm to the Xmas crust.
Recent wind drift at 6,100ft
Windy Pass
North face of Mt Stuart
Cashmere and the Black Pyramid
Dakobed (Glacier Pk) and Big Slide Peak.
NW at 7,500ft. Multiple thin, weak layers in the upper snowpack.
Some drifting snow was observed right near ridgetop. It was intermittent and didn't appear to be moving a lot of snow.
https://youtube.com/shorts/irl0cbb9YHQ?feature=share

Advanced Information

Weather Summary

Cloud Cover:
Mostly Cloudy
Wind:
Moderate , W

Mostly overcast with high clouds in the morning, gradually lessening and mostly clear by mid afternoon. Winds were moderate and gusty at times near ridgetop. Temperatures moderated through the day, but still felt fairly cold.

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Photos Details
1 Jan 15, 2023
() 		Edwards Mesa
N ft 		D3 N-Natural
Flow of very large wet avalanche, likely from around mid January. Lower arrow points to the tongue.
Very large wet avalanche.
Report
Edwards Mesa

Noticed an older D3 out of a path to the west of the Sleeping Lady gully on the north side of Edwards Mesa. I call it Sleeping Dragon. It came fairly close to one of the houses across Icicle Creek, and likely ran around MLK weekend.

Snowpack Observations

Overall the snowpack was right side up and strong on these northerly aspects. Weakening near surface structure was evident all day with slippery skinning and easy to identify sugary facets over the MLK crust. For now, ski crampons were helpful. Above 5,500ft we found some isolated areas of fresh wind drifting, though couldn't get any substantial fractures to occur on test slopes.

From bottom to top:
Icy, hard and firm at lower elevations.
At trailhead, Boot pen was 35cm, through the MLK crust into sugary facets.

At 4,300ft on NW aspect found HS of 135cm, with 18cm faceting snow over the MLK crust. MLK crust was weakening, and snow beneath was very weak, medium sized facets. 65cm down to the Xmas crust.

At 7,400ft the MLK crust disappeared, and at 7500ft on a NW aspect found HS of 193cm.
5cm down was a layer of recently buried surface hoar (2-5mm).
10cm down to where the MLK interface existed, with 1.5mm facets at the interface. Tilt tests failed with moderate force, suddenly and clean (see video).
28cm down was a layer of small grained, rounded facets (maybe the Jan 4th interface) that failed with CTM SP and CTM RP. ECTN 20 here.
The Xmas crust was down 93cm and had a couple inconsistent laminations, with P- hard snow on top.

Top to bottom:
Nice, recrystallized powder skiing in sheltered areas. Some wind stiffened snow in the open. Minimal sluffing or entrainment.
MLK crust made the skiing trickier as we descended, but in the open it remained ok. Challenging skiing in the thicker trees at lower elevations with refrozen and icy snow. What little I did see of the summer trail up Mountaineer Creek looked like an icy luge run.

WordPress Lightbox