22-23

Natural Republic Mountain

Date
Region
Cooke City
Location (from list)
Republic Mountain
Observer Name
Zach Peterson

Large natural avalanches near Cooke City

COOKE CITY
Cooke City
Code
N-R2-D2-O
Elevation
10000
Aspect Range
E,S,SW
Latitude
45.02020
Longitude
-109.93800
Notes

Near Cooke City (12/2/22) we rode to the cabins at Lulu Pass, then to Round Lake, then to Daisy Pass. Visibility was 50/50, so we didn't see all terrain clearly. We saw multiple large natural avalanches that broke last night or early this morning.

The largest were 3 on Scotch Bonnet (R2-D2, south-souwest aspect at 10,000'), 1 on Henderson in the big east facing slide path (R1-D2. east aspect 10,000'). These appeared to be 3-4 feet deep, and we suspect broke on a layer of weak snow that formed last week and is now buried 2-3 feet deep, and deeper on high wind-loaded slopes.

(We also saw 4-5 smaller wind slabs (R1-D1).)

Number of slides
4
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
36.0 inches
Vertical Fall
800ft
Slab Width
100.00ft
Images
Natural avalanches on Scotch Bonnet (far)
Natural avalanches on Scotch Bonnet
Natural avalanche on Henderson east aspect
Attached Videos
Natural Avalanches, Dangerous Conditions, Cooke City - 2 Dec
Snow Observation Source
Recent natural avalanches and snowpits
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
22-23

Goose Creek

Date
Activity
Skiing
Region
Northern Gallatin
Location (from list)
Goose Creek
Observer Name
Jackson

Recent natural avalanches and snowpits

Date
Activity
Skiing

Near Cooke City (12/2/22) we rode to the cabins at Lulu Pass, then to Round Lake, then to Daisy Pass. Visibility was 50/50, so we didn't see all terrain clearly. We saw multiple large natural avalanches that broke last night or early this morning. The largest were 3 on Scotch Bonnet (R2-D2), 1 on Henderson in the big east facing slide path (R1-D2) and 1 on Old Man Ray's on Republic Mtn (no photo). We also saw 4-5 smaller wind slabs (R1-D1). The larger avalanches we suspect broke on a layer of weak snow that formed last week and is now buried 2-3 feet deep, and deeper on high wind-loaded slopes. In a snowpit on West Henderson we had ECTP23 and ECTP24 about 2 feet deep on a layer of 1mm facets. Below that the snowpack seemed generally strong. Based on the recent natural avalanche activity, this is a weak layer we will have to keep an eye on going forward, and it could produce human-triggered avalanches for at least the next few days.

Region
Cooke City
Location (from list)
COOKE CITY
Observer Name
Alex Marienthal
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