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Observations

Region: Turnagain
Location: Skier Triggered Avalanche on North side of Magnum
Observer:
Date:

Route & General Observations

Sunburst lot to Taylor Pass (3500′)

Avalanche Details

Avalanche details

Trigger SkierAvalanche Type Aspect North
Elevation 3800ftSlope AngleunknownCrown Depth2ft
Width 300ftLength 1000ft  

Observer Comments

On April 1st a skier triggered a large avalanche on a Northern aspect of Magnum in a chute known as "Basketball Chute." There were two skiers in the party and the first skier triggered it after making three turns in a rocky area where the gully widens. The second person in the party skied down the bed surface and started a beacon search, but then spotted the skier below him on the debris. The skier was able to stay on top of the debris and didn't lose any equipment in the slide. No one was buried or injured. The avalanche happened at approximately 5pm.

The above measurements are approximate. The length of the slide path was closer to 1300'.
SS-Su-R3-D2-O

Red Flags

Obvious signs of instability

Recent Avalanches?YesCollapsing (Whumphing)?NoCracking (Shooting cracks)?No

Observer Comments

The party didn't see any recent avalanche that day. They had also skied a similar aspect and Northern chute (Corner Pocket) on Cornbiscuit earlier that day. They did not feel or hear any collapsing or see any shooting cracks.

Weather

Weather

Temps: 30-40 F
Sky: Overcast and became partly cloudy later in the day
Winds: Light
No Precip

Snow Characteristics

Snow surface

Morning: 1-3" of low density snow sitting on a stout crust below 2000'
Afternoon: Damp soft snow on stout crust
Above 2000': 4-4" of new snow
*Southern aspects had new rollerballs in the afternoon from the recent new snow heating up around rocks.

Snowpack

North Aspect at 3500' - HS=195cm. Slope angle= 32*. 60cm of snow from the last week sitting a few different layers of facets and crusts. The overall structure was poor, but a lot of force was required to fail the weak layer 75cm below the surface. The weak layer was a 4F hard layer of facets sandwiched between two crust layers. The upper crust layer was pencil hard and was only 2cm thick. The crust layer below was Knife hard. Test scores indicated that it required a lot of force to initiate the weak layer, but once it failed the slab suddenly collapsed and easily slid out of the pit. The slab was Fist hard at the surface and gradually became denser and was pencil hard near the bottom. Test Scores were ECTP29 SC, ECTX (32 taps SC)

*Test results confirmed that we were digging in an area representative of the snowpack in "Basketball Chute." We specifically chose the site based on its similar elevation and aspect.

WSW aspect at 3500' - HS=180cm, 50cm of snow was sitting on a 2cm Knife hard melt/freeze layer. The snow above and below this crust pencil hard. Overall structure was good and no obvious weak layer was found in the top meter of snow. ECTX

Photos & Video

Video

Photos



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