Repeat Offender

Location Name: 
Repeat Offender
Region: 
BWRA
Date and time of avalanche (best estimate if unknown): 
Thu, 01/17/2019 - 02:49
Location Map: 


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Rapid warming
Obvious avalanche path
Terrain Trap

Observation made by: Avalanche Specialist
Avalanche Observations
Avalanche Type: 
Dry
Slab
Slope: 
43degrees
Trigger type: 
Natural
Crown Height: 
5 ft
Aspect: 
Northeast
Weak Layer: 
Storm Snow
Avalanche Width: 
250ft.
Terrain: 
Near Treeline
Elevation: 
9 600ft.
Bed Surface: 
Old Snow
Avalanche Length: 
1 100ft.
Number of similar avalanches: 
More than 10
Number of people caught: 
0
Number of partial burials: 
0
Number of full burials: 
0
Did the avalanche hit a building, vehicle, or structure?: 
No
More detailed information about the avalanche: 

This avalanche path has a feroucious frequency when we have Atmospheric River events. The aspect & descending ridgeline cornice has a way of collecting snow in an unstable fashion. This lower elevation slide path also receives an abundance of rain in these seasonal weather phenomenons, adding a Wet/(Moist) Slab component. The aptly named "Repeat Offender" has a total length of 1100' with its starting zone at 9600' on a NE aspect. The terminus of debris collects in a canyon terrain trap that faces SE. Just above the terrain trap is Leavitt Lake Road, a popular travel route for snowmobilers & training Marines. During recent heavy snow, rain & wind a slab of collected snow became saturated & unstable, releasing a Soft Slab Avalanche N-SS-R3-D4-I. The accretion of dense snow avalanched through a patch of old-growth forest, over the road, & filled in the canyon drainage which sypathetically released a slab on the opposing river bank. Trees with over a foot DBH were cleared from their stumps. Island pockets of hang-fire still linger in the starting zones adjacent to this avalanche path. To the NE of this avalanche path another slide path called "Little Buddy" also released with less dramatic effect.

Avalanche Photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Above Freezing
Wind Speed: 
Moderate
Precipitation: 
Rain
Air temperature trend: 
Static
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Thick coastal clouds lingered nearly all day. The air was super-saturated and spitting rain above Sonora Pass @ 9700'. We had moments of sun & visibility to the alpine, finding multiple crowns.