Date of Observation: 04/02/2023
Name: Zach Guy
Zone: Northwest Mountains
Route Description: Morning tour on Mt. Emmons, traveling on southerly and northerly aspects to 12,000′
Observed avalanche activity: Yes
Avalanches: Several notable large avalanches that ran sometime since Evan was on Mt. Emmons yesterday morning. These likely ran during Saturday afternoon’s peak warming, or the cornice falls could have happened overnight. Plus a few older wind slabs that likely ran during Friday’s storm.
-A second cornice fall in Redwell Basin, extending dirty debris further than the slide in the same area that Evan documented yesterday, and prying out a couple of slabs in the upper snowpack, ~D2.5 to D3 in size.
-Several wide D2 to D2.5 storm slabs that ran on the southwest side of Schuylkill Ridge to valley floor in OBJ, snapping several trees.
-A large wind slab in Peeler Basin that was triggered by cornice fall, D2.
Weather: Strong winds above treeline and moderate winds below treeline were helping to keep snow surfaces cool today. Winds appeared to be sublimating the drifting snow more than loading. Few clouds. Spring temps.
Snowpack: Skied steep, north-facing terrain with no signs of instability. On solar aspects, crusts started to soften around 11 or noon. I didn’t see any active rollerballs or wet loose activity by the time we left at 1 p.m. I stomped around above a wind-loaded east-facing slope midday and couldn’t produce any signs of instability.
Photos:
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Several large storm slabs that ran off of Schuylkill Ridge yesterday afternoon and reached valley floor.
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A closer look at one of the crowns on Schuylkill Ridge.
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A cornice fall that overlapped with the cornice fall that Evan observed yesterday morning. This one ran further and pried out a couple of slabs.
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A wind slab triggered by a cornice fall, sometime since yesterday morning.
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A pair of large wind slabs in Wolverine Basin. I think these ran during the storm on Friday.
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A closer look at the previously documented storm slabs on Anthracite Mesa that ran yesterday afternoon.
Estimated avalanche date: 04/01/2023
Number of Avalanches: 1
Location
Location: Peeler Basin
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: E
Characteristics
Trigger: Cornice fall
Trigger modifier:
Type: Soft Slab
Failure Plane:
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: Ran sometime between midday 4/1 and morning of 4/2.
Estimated avalanche date: 04/01/2023
Number of Avalanches: 1
Location
Location: Mount Emmons
Location Specific:
Start Zone Elevation: ATL: Above Tree Line
Aspect: NE
Characteristics
Trigger: Natural
Trigger modifier:
Type: Cornice
Failure Plane:
Size
Relative Size: R2 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: Redwell Basin. Ran sometime between midday 4/1 and morning of 4/2. Overlapped with previous cornice fall first observed morning of 4/1, so difficult to assess size. Somewhere in the 2.5 to 3 range. Pried out a couple of slabs.
Estimated avalanche date: 04/01/2023
Number of Avalanches: 2
Location
Location: Schuylkill Ridge
Location Specific:
Start Zone Elevation: BTL: Below Tree Line
Aspect: SW
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane: New/Old interface
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: Ran afternoon 4/1
Estimated avalanche date: 04/01/2023
Number of Avalanches: 1
Location
Location: Schuylkill Ridge
Location Specific:
Start Zone Elevation: BTL: Below Tree Line
Aspect: SW
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft 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: Ran afternoon 4/1
Estimated avalanche date: 03/31/2023
Number of Avalanches: 2
Location
Location: Mount Emmons
Location Specific:
Start Zone Elevation: NTL: Near Tree Line
Aspect: E
Characteristics
Trigger: Natural
Trigger modifier:
Type: Soft Slab
Failure Plane:
Size
Relative Size: R2 small
Destructive Size: D2 – could bury, injure, or kill a person
Avg. crown height (inches): 24
Avg. width (feet):
Avg. vertical run (feet):
Involvements
# of people caught:
# of partial burials:
# of full burials:
Additional comments: Wolverine Basin. Failure date estimated.
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