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Professional Observation

Basic Information

Observation Details

Observation Date:
January 15, 2020
Submitted:
January 15, 2020
Observer:
SAC - Lundy (off duty)
Zone or Region:
Banner Summit
Location:
Glassing from Stanley to Cape Horn

Signs of Unstable Snow

Recent Avalanches? 
Yes
Cracking? 
None Experienced
Collapsing? 
None Experienced
See notes below on natural activity

Bottom Line

Significant avalanche cycle in the Banner Summit area and the northern Sawtooths (likely more extensive but this is just what I observed today) due to 3"+ water since 1/10 on several buried weak layers. Maybe premature to draw patterns, but most activity was occurred on upper elevation, shady slopes that likely had October snow. Most did not go at the ground, so most likely running on facets above the crust that capped the basal depth hoar, similar to what Ben saw yesterday on Banner Summit. But can't rule out the 12/7 surface hoar as a possible culprit.

Media

Fuzzy image of the skiers R side of Copper North Side

Advanced Information

Avalanche Observations

 #  Date Location Size Type Bed Sfc Depth Trigger Comments Photo
2 Past 48 hours Merritt Peak, N Sawtooths
NE 10000 		D3 HS O-Old Snow N-Natural Both of the bowls on the east side of Merritt ran, likely loaded from overhead cliff terrain.
Numerous large, deep slab avalanches released in the Sawtooths during the extended storm cycle that began January 10th. Many were visible today thanks to good visibility. 3-4 feet of new snow overloaded several buried weak layers deep in the snowpack.
Numerous Past 48 hours N Sawtooths
 D3 See Tanner Haskin's ob with numerous photos from the north end of the Sawtooths. Numerous D2-3 deep slabs in alpine terrain, many obviously loaded from overhead cliffs or ridge level wind loading None
Several Past 24 hours North side of Copper Mountain and the Unknowns
NE 8960 to 8700 		D3 HS G-Ground U-Unknown Northside of Copper and the Unknowns ran more or less wall to wall
Several Past 48 hours Copper Mountain ridgeline south of Copper Mtn
NE 8700 		D3 HS O-Old Snow U-Unknown Largest ran in terrain that probably had some wind effect but was somewhat sheltered. Other slide (left side of photo) ran in terrain that ran in mid December on surface hoar.
Numerous large, deep slab avalanches released in the Banner Summit area during the extended storm cycle that began January 10th. Many were visible today thanks to good visibility. 3-4 feet of new snow overloaded several buried weak layers deep in the snowpack.
Many Past 48 hours Peak 9158 near head of Swamp Creek and adjacent terrain
N 9158 to 8500 		D3 HS O-Old Snow N-Natural
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