Date of Observation: 04/28/2023
Name: Zach Guy
Zone: Northwest Mountains
Route Description: Upper Slate and Yule Pass areas. Traveled mostly on easterly and northerly aspects to 12,600′
Observed avalanche activity: Yes
Avalanches: On north-facing terrain ATL, I skier triggered a thin wind slab (~6″ x 8′) and a loose dry avalanche that both ran about 800′ (D1s).
Wednesday’s sunny weather after the storm spurred a wet shed cycle around the compass except for high northerlies. These were mostly wet loose, D1-1.5, and a handful of slabs up to D2. Not sure if they were moistening storm slabs or wet slabs; the debris looked fairly wet.
Weather: Clear, unseasonably cool temps. Moderate northwest winds were blowing the 1″ of new snow around with small plumes off of high peaks.
Snowpack: 1″ of new overnight and winds formed isolated, thin wind slabs ATL. These appeared to be bonding well on solar aspects; got one to pop on a crossloaded north facing slope. There’s up to 10″ or so of recent storm snow from the Tuesday night storm which hasn’t fully transitioned yet and could continue to produce more wet loose activity this weekend, especially to human triggers. At 1 p.m. while skinning up Yule Creek (~10k’, fairly flat terrain), we were getting widespread collapses on the dust layer, which was about 6″ to 8″ deep and saturated. Most collapses were a ski length or two wide, but some produced shooting cracks up to 30′ or 40′. This suggests there is potential for thin wet slabs this weekend as well, similar in character to the avalanches on Schuylkill Ridge shown below.
Photos:
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[accordion_item title=”Avalanche Report #1″ parent_id=”my-accordion” open=”false”]Estimated avalanche date: 04/28/2023
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: Skier
Trigger modifier: Controlled
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): 800
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Thin wind slab. The Ant.
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Estimated avalanche date: 04/28/2023
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: Skier
Trigger modifier: Controlled
Type: Loose
Failure Plane:
Size
Relative Size: R1 very small
Destructive Size: D1.5
Avg. crown height (inches):
Avg. width (feet):
Avg. vertical run (feet): 1000
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: The Ant
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Estimated avalanche date: 04/26/2023
Number of Avalanches: 3
Location
Location: Schuylkill Ridge
Location Specific:
Start Zone Elevation: NTL: Near Tree Line
Aspect: E
Characteristics
Trigger: Natural
Trigger modifier:
Type: Unknown
Failure Plane: New/Old interface
Size
Relative Size: R2 small
Destructive Size: D2 – could bury, injure, or kill a person
Avg. crown height (inches): 10
Avg. width (feet): 200
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Slab releases. Failure date estimated. Not sure if these were wet slabs or moistening storm slabs. Debris was wet.
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Estimated avalanche date: 04/26/2023
Number of Avalanches: 40
Location
Location:
Location Specific:
Start Zone Elevation:
Aspect:
Characteristics
Trigger:
Trigger modifier:
Type: Wet Loose
Failure Plane:
Size
Relative Size:
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: All aspects and elevations except high north. D1 to D1.5
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