Date of Observation: 12/08/2022
Name: Eric Murrow
Zone: Northwest Mountains
Route Description: Snowmobiled Kebler Pass to West Beckwith.
Observed avalanche activity: Yes
Avalanches: Lots of large natural avalanches were observed near/above treeline on the north half of the compass in the Anthracite Range, East Beckwith, and West Beckwith. Some avalanches appeared very fresh, within the past 24 hours, while others appeared to be closer to 48 hours from the tail end of Tuesday’s storm. Visibility was marginal; I observed many debris piles with obscured start zones, or binoculared a crown but was unable to photograph before losing visibility. I coded avalanches in the attached photos.
Did not observe any avalanches below treeline.
I got a few glimpses into southerly terrain north of Dark Canyon, and southeasterly terrain on Marcellina and did not observe any obvious large avalanches.
Weather: Snowfall tapering off by 10 am. Partly to mostly cloudy skies. Westerly winds were transporting moderate amounts of snow at upper elevations. 24-hour snowfall totals ranged from 2 to 5 inches along the Kebler Pass roadway.
Snowpack: I took a moment to dig a profile on a northerly slope at 9,000 feet near Horse Ranch Park. Snow depth was 80cm. The bottom 15cm was 2-3mm depth hoar, with around 30cm of 1-finger and 4-finger hardness slab above, and about 35cm of lower-density recent snow at the surface. I was able to walk around in boots and not punch through the slab. I believe I collapsed the site as I approached on my snowmobile. The snowpack in the western parts (west of Kebler Pass) of the Northwest Mountains seems to match well with the rest of the zone in the Ruby Range based on the profile and snow coverage in alpine terrain.
Photos:
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Natural avalanche off East Beckwith. The brown stain suggests it ran sometime after sunrise on Thursday 12/8. Debris pile not visible from my vantage.
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A widely propagating avalanche on north-facing terrain of West Beckwith.
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A wide avalanche in north-facing terrain of West Beckwith.
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A pair of avalanches from East Beckwith. One looks to be a day or so old, while the crown looks sharp in the right basin.
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An avalanche on northwest-facing terrain of East Beckwith immediately above Lost Lake Slough.
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An avalanche off East Beckwith that drains into Cliff Creek. There was an avalanche off the obscured high point but I was not able to get a good look.
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A wide avalanche with a relatively sharp crown in “Northwest Bowl”. The classic “AMR” ski terrain is just out of frame to the left.
Estimated avalanche date: 12/08/2022
Number of Avalanches: 1
Location
Location: Anthracite Range
Location Specific:
Start Zone Elevation: NTL: Near Tree Line
Aspect: N
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R2 small
Destructive Size: D2 – could bury, injure, or kill a person
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Appeared to have failed recently. Poor vis but estimate early AM on 12/8
Estimated avalanche date: 12/08/2022
Number of Avalanches: 2
Location
Location: Beckwith Range
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: NE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R1 very small
Destructive Size: D2 – could bury, injure, or kill a person
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: 1 – path that went historic last Decemeber. 2 – basin west of summit
Estimated avalanche date: 12/06/2022
Number of Avalanches: 2
Location
Location: Beckwith Range
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: N
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R1 very small
Destructive Size: D2 – could bury, injure, or kill a person
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: 1 – basin that drains into Cliff Creek visible from Beckwith Pass 2 – north summit basin on west edge. Both appeared to have slightly subdued debris so I coded prior to Thursday’s event
Estimated avalanche date: 12/06/2022
Number of Avalanches: 1
Location
Location: Beckwith Range
Location Specific:
Start Zone Elevation: NTL: Near Tree Line
Aspect: NW
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R2 small
Destructive Size: D2 – could bury, injure, or kill a person
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Basin to east of summit directly above Lost Lake Slough. Debris appeared to have some snow on it so coded prior to 12/8 event.
Estimated avalanche date: 12/06/2022
Number of Avalanches: 1
Location
Location: Beckwith Range
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: N
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: Old snow
Size
Relative Size: R1 very small
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: Eastern most basin on West Beckwith. Widely propagating so coded as D2.5. Appeared to have some snow refill so I coded prior to 12/8 event.
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