Date of Observation: 01/09/2022
Name: Eric Murrow
Zone: Northwest Mountains
Route Description: Anthracites
Observed avalanche activity: Yes
Avalanches: An unreported avalanche below treeline on a northeast-facing slope from near the middle portion of the Anthracites skin track. Did not inspect the crown, but it hammered the typical skin track breaking at least one tree, 5 inches in diameter, and toppling several others over. Crown looked around 4 – 5 feet thick. I suspect it ran towards the end of holiday storms around 12/30. This is the second time this winter that the Anthracite skin track has been impacted by a natural avalanche.
Small natural Wind Slab from 1/8 beneath a cornice in East Bowl.
Weather: Sunny skies and reasonable temperatures above the inversion. Light winds at ridge top.
Snowpack: I looked for buried surface hoar in several spots on north and northeast aspects and didn’t find it. Traveled through a northerly near treeline feature that often forms Wind Slabs and found only soft storm snow. No cracking in storm snow or signs of instability in terrain with snow depths well over 2 meters. Southerly slopes below and near treeline became moist by the afternoon.
Photos:
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[accordion_item title=”Avalanche Report #1″ parent_id=”my-accordion” open=”false”]Estimated avalanche date: 12/30/2021
Number of Avalanches: 1
Location
Location: Anthracite Range
Location Specific:
Start Zone Elevation: BTL: Below Tree Line
Aspect: NE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Hard Slab
Failure Plane:
Size
Relative Size: R3 medium
Destructive Size: D2.5
Avg. crown height (inches): 48
Avg. width (feet):
Avg. vertical run (feet): 300
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Slope where skin track leaves runout of 7 bowl to gain broad ridge to summit. Could be D3, but hard to say now that debris is buried but given short vertical of 300 feet. Impact pressures were high but total volume was likely short of D3. Hard to know how many trees got wacked.
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