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Snowmobile triggered wind slab in the Old Ski Bowl
Location Name:
Old Ski BowlRegion:
Mt. ShastaDate and time of avalanche (best estimate if unknown):
Sat, 01/27/2018 - 11:00amObservation made by:
ForecasterRed Flags:
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Rapid warming
Location Map
96067
Mount Shasta
, CA
United States
41° 22' 4.3968" N, 122° 11' 47.4252" W
See map: Google Maps
California US
Avalanche Observations
Details
Characteristics
Avalanche Type:
DryTrigger type:
SnowmobilerSlope:
35degreesAspect:
EastElevation:
8 400ft.Terrain:
Above TreelineWeak Layer:
Storm SnowBed Surface:
Storm SnowCrown Height:
3 ftAvalanche Width:
250ft.Avalanche Length:
20ft.Number of similar avalanches:
1Number of people caught:
0Number of partial burials:
0Number of full burials:
0Weather Observations
Details
Strong westerly winds were steady throughout the day. In the afternoon, a brief rain event occurred up to 8,000ft. Skies were mostly obscured with short periods of sunshine.
Statistics
Cloud Cover:
75% of the sky covered by cloudsBlowing Snow:
YesPrecipitation:
RainAccumulation rate:
NoneAir temperature:
Above FreezingAir temperature trend:
WarmingWind Speed:
StrongWind Direction:
West
SS-AM-R4-D1-S (soft slab, artificially triggered by a snowmobile, large relative to the avalanche path, relatively harmless destructive force, bed surface within new snow)
A snowmobile triggered wind slab avalanche occurred today on an east-facing slope above treeline at 8,400ft in the Old Ski Bowl. The avalanche broke 1-3ft deep, 250ft wide, and ran 10-20ft downslope. The avalanche failed on a density break within new snow. No one was caught, buried or injured. Westerly winds were actively loading leeward slopes and terrain features near and above treeline. Although this was a relatively harmless avalanche, the propagation was very impressive.