Avalanche: Hatcher Pass

Location: $1000/ April Bowl

Date:
Observer:
Barker Kayes Forecaster
Route & General Observations

Toured up $1000 run to April Bowl to assess stability at upper elevation after 12/18-22 storm. Observed large D2 natural in April Bowl. No whumping, cracking, or collapsing observed on our tour today.

 

Avalanche Details
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Trigger NaturalRemote Trigger Unknown
Avalanche Type Hard SlabAspect North Northwest
Elevation 4700ftSlope Angleunknown
Crown DepthunknownWidth 1000ft
Vertical Rununknown  
Avalanche Details

We traveled up to April Bowl and observed a large D2 natural avalanche that likely occurred on 12/21 or 12/22 after a recent load of approx. 10" of new snow combined with strong to extreme gusts 30-50 mph for 24 hrs. The crown was approx 1000 feet wide and a few feet deep. We believe it failed on old near surface facets (now rounding facets) that can be found 2-4 feet deep in the snowpack.

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?No
Observer Comments

Recent avalanches from 12/21,12/22 (?) as a result of new snow and moderate to strong ESE/SE winds with strong to extreme gusts 30-50mph for 24 hours on 12/21-12/22.
Natural avalanches observed in April Bowl (NW 4700') Rae Wallace (NW 4500') above 10 mile (NE approx 2000-2500' )
Remotely triggered avalanches on 12/22. See Jake Kayes Obs 12/22.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Weather

16" new snow 12/19-23
Moderate to strong wind with strong to extreme gusts 30-50 mph for 24 hrs on 12/21 and 12/22
Increasing temps throughout the first part of the storm. Ice pellets fell during the storm (and are buried), showing the warmth of the storm (at the cloud layer)
12/23 4500'
1000: 19F, S15 G29mph S2
1200: 18F, SSW 12 G24mph S1
1400: 19F, S6 G18mph S1

Snow surface

Variable conditions everywhere. 1-2' thick wind slabs with 6" new snow from 12/22-23, wind board, old melt-freeze crusts, and possibly some new snow in very protected locations.

Snowpack

Pit 1: 4400' W/NW HS 195cm, ECTP 29 60cm down on rounding facets, CT14 RP 30cm down on ice pellets
Pit 2: 4400' W/NW HS 140cm, ECTN26 60 cm down on rounding facets
Pit 3: 3800' N HS 80 cm, ECTX

Photos & Video
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Wind stripped ridges from 30-50 mph wind gusts for 24 hours 12/21-22  

Skyscraper south aspect 12/23  

April Bowl N/NW 4700' D2 Natural likely 12/21 or 12/22  

Ice pellets found in the new snow 12/23  

Location
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