Loose Wet Avalanche on Basin Mtn

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AVALANCHE OBSERVATION
Basin Mtn
Submission Info
Forecaster
Saturday, April 15, 2017 - 11:45am
Red Flags: 
Rapid warming
Obvious avalanche path
Avalanche Type: 
Wet
Loose/Point-Release
Slope: 
35degrees
Trigger type: 
Skier
Aspect: 
East
Weak Layer: 
Other - explain below
Avalanche Width: 
30ft.
Terrain: 
Above Treeline
Elevation: 
12 200ft.
Bed Surface: 
Old Snow
Avalanche Length: 
800ft.
Number of similar avalanches: 
1
Number of partial burials: 
0
Number of full burials: 
0
More detailed information about the avalanche: 

Traversed into wet snow (boot top ski penetration) on an E aspect to take a photo of a natural D1 loose wet that we'd seen run about 30 minutes earlier and triggered this D1.5-D2. Ran on an older melt-freeze crust that was 10-30cm below the surface depending on aspect. Debris was about 2' deep. Still big enough to take you for a ride and probably mess up your knees. We were easily able to avoid it and manage the risk of other releases by staying on more northerly aspects.

Avalanche Photos: 
Avalanche observation video: 
More detailed information about the weather: 

Route- From Horton Lakes rd up the moraine below Basin Mtn. to the top of the main chute. Back down the same way. Tracking melting and wet snow instabilities at higher elevations.

0830 at 9200' on an E aspect on the bottom of the moraine- Tair = 4 C, Tsurf = -1 C, Foot pen = 5cm, surface still frozen melt-freeze crust.

0900 at 9960', E aspect in the middle of the moraine- Surface stating to soften. Ski pen = 2cm, to 3cm of snow moist.

0915 at 10480' on a NE aspect just before the slight drop from the top of the moraine into the basin- Tair = 6 C, Tsurf = 0, T-20= -3 C, Foot pen = 20cm. Surface snow was moist MFcr.

1000 at 11400', NE aspect in the middle of the basin before starting the climb up the chute- Tair = 7 C, Tsurf = 0 C, Foot pen = 3cm. Surface snow was P hard wind board, top 1cm becoming moist.

1100 at 12400' booting up the chute- Saw a small (D1) natural loose wet release from between some rocks on a steep (>35 deg.) SE aspect.

1115 at 12800' at the top of the chute, NNE aspect- Tair = 2.5 C, Tsurf = -3 C, Foot pen = 2cm. Surface snow was P hard wind board.

1145- Triggered loose wet on E aspect.

1200 at 10480' (same spot as 0915 observation)- Tair = 9 C, Tsurf = 0 C, Foot pen 10cm. Surface snow wet.

Sky went from Scattered hazy clouds to Broken hazy clouds throughout the day. Winds were Calm. At the top of the chute winds were Calm with Light gusts from the SW.

Number of People Caught: 
0
37° 18' 8.9172" N, 118° 39' 18.018" W

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