Avalanche: Summit

Location: Fresno

Route & General Observations

Fresno to 2300′

Avalanche Details
If this is an avalanche observation, click yes below and fill in the form as best as you can. If people were involved, please provide details.
Trigger NaturalRemote Trigger Unknown
Avalanche Type UnknownAspect Unknown
ElevationunknownSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

Two avalanches - one ~D2.5 on a NE aspect of Colorado and the other a D2 on a NW aspect gully on Butch - that likely occurred overnight. Each started close to wind scoured ridgelines and debris looked to be slightly covered by new snow. There may have been other slides in the region... light was fairly flat throughout the day, and even these two weren't obvious when clouds were overhead.

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?No
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

Short cracks - some 6" deep - on the ridgeline where winds loaded small terrain features overnight.

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

Overcast to broken skies, occasional light winds from the south
Temps in the 20s down low, teens up high
Very brief period of very light snow mid afternoon

Snow surface

6-8" of new snow fell overnight! This surface layer was barely cohesive enough to stick together in hasty hand pits, and would shear from the old snow layer with light force. Except for on the ridgeline where overnight winds made small slabs that cracked underfoot, the new snow layer lacked cohesion to crack in areas showing no sign of wind affect (nearly every slope we traveled today). Ski penetration of 6 - 12" along the route.


Dug a pit - 2150', E aspect, 25 degree slope - to look at the Thanksgiving Crust, just off the ridgeline at a location that was slightly wind scoured before the overnight storm (height of snow was 100cm). In each of three pits over the weekend in the area, the faceting in and around the Thanksgiving Crust was different, but CTs would only fail under hard force if at all, and ECTs wouldn't fail by 30 taps (ECTX). That said, today's pit also had a consistent, thin weak layer that was suitable to test with a Propagation Saw Test, and it failed with a result of 35/100 END. Yesterday a pit on Colorado had a similar result (30/100 END), and both are considered unstable test results. See pit profile below!

Photos & Video
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