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PROFESSIONAL OBSERVATION FORM
 Start Date: 01.21.19 Name: Lundy Operation: SAC
 Drainage/Route:  Glassing from Alturas to Stanley to Copper Observed Terrain:   Zone/Region:  Sawtooth Mountains
WEATHER OBSERVATIONS
 HN24: HST: Sky: Precip: Temps:
 Ridgeline Wind:
 Blowing Snow: Snow Available for Transport:
 Comments: Looked like NW winds were still transporting snow up high. Significant wind effect in the alpine
AVALANCHE OBSERVATIONS
None Reported
 Comments: This past storm produced numerous avalanches in the Sawtooths zone. I observed several persistent and deep slab avalanches. A few released midstorm - a couple seemed to be filled in like the Crooked Creek slide Scott reported yesterday AM. A few others looked very crisp and likely released last night/early this morning. The photos below show the most significant persistent slabs. Numerous other storm/wind/spindrift slabs released near the end of the storm, most were less than D2 in size - with the possible exception of the Decker slide shown below.

The Meadow Bowl avalanche was on a different scale than the other persistent slabs, with deep spindrift cones on the apron breaking down to the 11/22 layer. There appears to be an ice crust on the bed surface from the October snow?

The majority of the persistent slabs were on upper elevation shady aspects but I'm not sure if that's really an important pattern. It appears wind loading played a role in most of them.

At least one slide south of Copper Mountain had run once, if not twice, before this season.
STABILITY TESTS
 Stability Test Results:
SNOW STABILITY
 Snow Stability Rating for your observed area: Confidence: Trend:
BOTTOM LINE
 Comments: It seems like our question was answered - the remotely triggered deep slab on copper did in fact seem to be a warning of deep persistent issues to come.
FILE ATTACHMENTS

191021-meadowbowl-deepslab.jpg
Meadow Bowl. D3.5, 9200', NE. Estimated 400' wide, 5-15' deep. Deep slab failing on 11/22 DH. Oct Ice crust visible in places. Ran 1200 vertical feet.

191021-meadowbowl-deepslab-closeup.jpg
Meadow Bowl crown.

190121_swamp_lake_pk_persistent_slab.jpg
Swamp Lake Peak on south end of Copper Mtn ridgeline. D3, 9200', NE. 700' wide, 2-3' deep. Likely ran on basal facets/depth hoar.

190121-iron-goat-divide-deep-slab.jpg
Iron/Goat Creek Divide in N Sawtooths. D2.5, 8800', NE. 200' wide, 2-3 feet deep. Likely ran on basal facets/depth hoar. Note ski tracks on sunny ridgeline - it's possible this was remotely triggered.

190121-decker-slab.jpg
Decker Peak. D2.5, 10000', E. Estimated 200' wide, 2-4' deep. Failure layer unknown, likely storm slab triggered by loading from overhead cliffs.

190121-iron-cr-persistent-slab.jpg
Iron Creek. D2, 8000', SE. Failure layer unknown, but has the appearance of a persistent weak layer - possibly crust/facets?

190121_s_of_gmogul_persistent_slab.jpg
South of Grand Mogul. D2.5, 9400', NE. Estimated 2-3 feet deep. Looks to have run on weak snow near the ground.

190121-crooked-cr-persistent-slab.jpg
Head of Crooked Creek. D2, 9500, NE. Persistent slab reported by Savage on 1/20/19. Filled in by overnight snowfall.

190121-mcgown-persistent-slab.jpg
McGown Cirque. D2, 9100', E. 2-3' deep. Likely persistent slab.