Date of Observation: 03/28/2023
Name: Zach Guy and Eric Murrow
Zone: Southeast Mountains
Route Description: Cement Creek, Hunter Hill, Star Pass, and Carbonate Hill. Various aspects to 13,000′
Observed avalanche activity: Yes
Avalanches: An impressively wide persistent slab avalanche across the E/NE side of Teo Ridge looks fresh in the past 48 hours, 2300′ wide on Google Earth. Snowmobile triggered a couple of 2′ wind slabs above treeline, one remotely, one with a slope cut, and there were a few recent natural wind slabs. Documenting older avalanches from the past week in a separate ob.
Weather: Clear to few clouds, below freezing temps in the alpine. Light winds with transport on a few terrain features.
Snowpack: Recent wind slab formation was localized to terrain features with large fetches for northwest winds; they were sensitive to slope cuts on the 3/24 crust, which looks lightly faceted. No signs of deeper instabilities under the sled today. A pit on an east aspect near treeline produced non-propagating failure on the 3/20 faceted crust under a 55cm soft slab. Snow surfaces stayed cool enough to keep wet loose activity at bay; the only wet loose activity I saw was in the steep, cliffy terrain around Mt. CB this afternoon.
Photos:
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Very wide persistent slab on Teo Ridge, looks fresh in past 48 hours. The red is an older slide from 3/22 cycle.
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Remotely triggered wind slab up to 2′ thick on 3/24 crust.
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Small wind slab on Carbonate Hill.
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Test pit, east aspect ATL.
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Snowmobile triggered wind slab.
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Several avalanches on Timbered Hill. The blue ones look fairly recent (a few days old or less). The red is from the 3/22 storm.
Estimated avalanche date: 03/28/2023
Number of Avalanches: 1
Location
Location: Cement Creek
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: S
Characteristics
Trigger: Snowmobiler
Trigger modifier: Remote
Type: Soft Slab
Failure Plane: New/Old interface
Size
Relative Size: R2 small
Destructive Size: D1- Relatively harmless to people
Avg. crown height (inches): 18
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Hunter Hill, wind slab. Remotely triggered from about 40 feet away. Failed on 3/24 crust
Estimated avalanche date: 03/28/2023
Number of Avalanches: 1
Location
Location: East Brush Creek (Star Pass, Friends Hut)
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: SE
Characteristics
Trigger: Snowmobiler
Trigger modifier: Controlled
Type: Soft Slab
Failure Plane: New/Old interface
Size
Relative Size: R2 small
Destructive Size: D1- Relatively harmless to people
Avg. crown height (inches): 18
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Pearl Pass area, Wind slab failed on 3/24 crust.
Estimated avalanche date: 03/27/2023
Number of Avalanches: 1
Location
Location: Middle Brush Creek (Pearl Pass Road, Cumberland Basin, Twin Lakes)
Location Specific:
Start Zone Elevation: BTL: Below Tree Line
Aspect: E
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R3 medium
Destructive Size: D2.5
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Teo Ridge, E to NE aspect. Crown looks fresh, sometime in past 48 hours.
Estimated avalanche date: 03/27/2023
Number of Avalanches: 3
Location
Location: East Brush Creek (Star Pass, Friends Hut)
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: SE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane:
Size
Relative Size: R1 very small
Destructive Size: D1- Relatively harmless to people
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Wind slabs, Carbonate Hill area
Estimated avalanche date: 03/26/2023
Number of Avalanches: 2
Location
Location: East Brush Creek (Star Pass, Friends Hut)
Location Specific:
Start Zone Elevation: BTL: Below Tree Line
Aspect: E
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R1 very small
Destructive Size: D1.5
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: THC. Crowns look fairly fresh, sometime between 3/24 and 3/27
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