Date of Observation: 01/02/2022
Name: Zach Guy
Zone: Northwest Mountains
Route Description: Yule Pass (Purple, Treasury, Treasure, and Mt. Justice ridgeline)
Observed avalanche activity: Yes
Avalanches: This area seemed to be the bullseye for the most destructive slides of the cycle, generally D3 to D4 in size, most crowns looked crisp so they ran on 12/31. Impressive crown depths (up 12 to 15 feet) and some wild propagation across multiple start zones. Mostly on northerly and east aspects. A few of these are west of our forecast area, but they were significant enough to document here.
Photos:
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Purple Mountain
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The Ant. I think this is the most impressive crown I saw because it appeared to wrap across three start zones
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Treasury above North Pole Basin
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Treasure
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Looking west from Yule Pass (Purple, Blob, Nipple, Ant, Justice, etc)
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Towards Mt. Justice
Estimated avalanche date: 12/31/2021
Number of Avalanches: 3
Location
Location: Upper Slate (Purple, Yule Pass, Paradise Divide)
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: NE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Hard Slab
Failure Plane: Old snow
Size
Relative Size: R4 large
Destructive Size: D4 – could destroy a railcar, large truck, buildings, or swaths of forest
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Purple Mountain, Treasury (into North Pole Basin), and the Ant. The Ant’s crown appeared to wrap from N to NE to E across 3 start zones, the most debris was from the north side.
Estimated avalanche date: 12/31/2021
Number of Avalanches: 2
Location
Location: Upper Slate (Purple, Yule Pass, Paradise Divide)
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: NE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Hard Slab
Failure Plane: Old snow
Size
Relative Size: R4 large
Destructive Size: D3.5
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: The Nipple, The Blob, Treasure. Couldn’t see the runout on these and they could potentially be D4s
Estimated avalanche date: 12/31/2021
Number of Avalanches: 1
Location
Location: Upper Slate (Purple, Yule Pass, Paradise Divide)
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: N
Characteristics
Trigger: Natural
Trigger modifier:
Type: Hard Slab
Failure Plane: Old snow
Size
Relative Size: R4 large
Destructive Size: D3.5
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: The Blob
Estimated avalanche date: 12/31/2021
Number of Avalanches: 2
Location
Location: Upper Slate (Purple, Yule Pass, Paradise Divide)
Location Specific:
Start Zone Elevation:
Aspect: E
Characteristics
Trigger: Natural
Trigger modifier:
Type: Hard Slab
Failure Plane: Old snow
Size
Relative Size: R3 medium
Destructive Size: D3 – could destroy a car, wood-frame house, or snap trees
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Purple Mountain near Yule Pass and out near Ragged Peak
Estimated avalanche date: 12/31/2021
Number of Avalanches: 3
Location
Location: Upper Slate (Purple, Yule Pass, Paradise Divide)
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: NE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Hard Slab
Failure Plane: New/Old interface
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: Yule Pass on the Purple side and two near Mt. Justice
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