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Avalanche: Hatcher Pass

Location: Independence Mine

Date:
Observer:
Route & General Observations

 

Toured up the the Microdot moraine west of the Ray Wallace Chutes and to test slopes below Eldorado Bowl. Our party triggered several avalanches (including remotely) and observed rampant whumpfing, extensive shooting cracks, and rapid wind loading towards sunset. Crowns from several natural avalanches ranging from D1-D2 from the recent snow storm were seen on the Sunnyside of Hatch in large swaths, on the south aspect of Skyscraper, in a West Gully on Marmot, on an east aspect of lower Eldorado Bowl, the west aspect of Microdot, and the south aspect of upper Eldorado Bowl (Skyscraper). All natural avalanches appeared to have initiated on slopes >35 degrees.

Avalanche Details
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Trigger SkierAvalanche Type Soft Slab
Aspect West SouthwestElevation 3200ft
Slope Angle 36degCrown Depth 18in
Width 60ftVertical Run 80ft
Avalanche Details

Skinning up the moraine below Ray Wallace Chutes we triggered a SS-ASr-R3-D1.5-O/I on a 25 degree slope. We conducted a crown profile. Avanet profile below. The fracture initiated in the new / old snow interface, and stepped down to wind slab over buried near surface facets.

Another party skiing down slopes adjacent to ours 500 feet north remote triggered a D 1.5 avalanche that failed on the the new old snow interface.

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)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

Rapid wind loading with pluming observed on ridgetops from a south easterly wind throughout day. By 3 pm moderate winds were filling in our tracks rapidly at elevations of approx 3200 ft, and very large plumes could be seen off most ridgetops and peaks from a south easterly wind.

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

Obscured sky that deteriorated throughout day.
Light south easterly winds at 3200 ft and moderate winds with pluming off peaks at noon.
Moderate south easterly winds at 3200 ft and significant pluming off all peaks and ridgetops by 3 pm.
No precipitation.
Temps 32 degrees at 3200 ft.

Snow surface

Transitioned from light, settling powder at Independence Mind parking lot to consolidating powder that became cakey in places as we skinned higher to approx. 3200 ft to moraine below Ray Wallace. Settling powder from previous storm was definitely forming a soft slab.

On the other side of the road on test slopes below Eldorado Bowl the snow was forming a cakey soft slab in places and becoming a soft wind slab in others. Ski pen was as low as 4-5 cm in places where the new snow had stiffened up. Light wind effect noticed near sunset.

Snowpack

We dug pits at two different locations, conducting CTs, ECTs, and PSTs. Profile and test results for pit west of Ray Wallace Chutes attached.

For the test pit below Eldorado Bowl: 3200 ft elevation, 120* SE aspect, 24* slope, CT4 SP down 45 cm on new snow / facet interface. ECTP5 down 45 cm on new snow /facet interface, PST 25/100 (END) down 45

Bottom line - poor structure, high propagation potential, poor stability. A very touchy snowpack.

Photos & Video
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