Avalanche: Hatcher Pass

Location: Road Observations and Natural Avalanche on Marmot almost reaching road

Date:
Observer:
Route & General Observations

Road observations. Drove to IMB parkinglot.

Driving conditions were sketchball. Very strong winds through the Matanuska River Valley, in Palmer, and up to the Turner Store. From Turner up to Hatcher the winds were moderate. Powder was still available and widespread up to mid elevations at 11AM.

 

 

Avalanche Details
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Trigger NaturalRemote Trigger Unknown
Avalanche Type UnknownAspect Southeast
Elevation 4400ftSlope Angleunknown
Crown DepthunknownWidth 1000ft
Vertical Run 2000ft  
Avalanche Details

Marmot, Gully 1 (viewers left of Presidents Ridge), N-D2.5R3-O. Debris ran to within 50' of the road. Toe of debris pile was constrained to gully feature, approximately 100' wide x 20 feet deep.
Wind loading from the NE likely loaded the starting zone, overloading the weak facet layer, and naturally releasing. I scanned for tracks from people along the ridge line with binoculars but saw none. This avalanche occurred between last night and early this morning, my guess would be early this morning.
2 other smaller avalanches in this same drainage were noted.

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

A weak snowpack with poor structure that consistently releases natural avalanches up to D2 with moderate loading.
No signs of other avalanches, other than numerous natural slab avalanches along the Arkose ridge line facing Palmer, above the Glenn Highway.
Further inspection may reveal more avalanche evidence, however I had limited time and poor light looking towards Arkose ridge line from HP.

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

Winds gusting ot 91mph in Palmer.
Winds were light at IMB at 11am. Powder was still plentiful in this location.
Cold 0F, Clear.

Snow surface

3000' - Powder, F hard, 8-10" over curst surfaces. Lightly licked by wind.

Snowpack

No formal tests or pits

Winds that were forecasted for yesterday arrived late, picking up at 9pm last night.
The avalanche hazard spiked to considerable with rapid wind loading affecting the widespread buried weak facets near the ground. This is the same layer that has had similar results each time it is moderately loaded. Avalanches have repeated in the same paths.

Photos & Video
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