Avalanche: Summit

Location: Colorado

Route & General Observations

Toured 2400′ up Colorado to see what has been going on in the Summit area. I wanted to see what was up with the buried surface hoar layer and find out how high it rained. Dug a pit at 2000′. Based on forecasts and not being in the field for a while I rode mellow terrain at 2400′ with around 15cm snow. At 2000′ there was 10cm wet snow. Surface crust started around 1900′. The sun came out and it was an amazing day to shred low angle! The crust was just ok.

Avalanche Details
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Trigger CorniceRemote Trigger Unknown
Avalanche Type Hard SlabAspect East Northeast
Elevation 4000ftSlope Angle 40deg
Crown DepthunknownWidth 400ft
Vertical Run 3500ft  
Avalanche Details

It looks like a cornice broke at the ridge line triggering a soft slab on the new/old snow interface but stepped down to a layer a third of the way down. This propagated up the drainage to the ridge in the sun where the crown is easily visible. Debris field looked liked hard slab chunks as well as soft snow. D3 in size.

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

Avalanche on Butch. Numerous point release avalanches on south aspects including Manitoba south up to 3200'.

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

Broken skies at 2pm, clear skies at 4pm. Clouds receding to the north. Valley fog forming quickly at 430pm. Winds light from the south turning calm. No precip.

Snow surface

15cm soft snow @ 2400'. At 2000' 10cm wet snow, @ 1900' crust to the highway.


I found the BSH in Hand Shear tests with easy results at 1600, to 2400 but it was unreactive in my snowpit. I dug a pit at 2000' on an 32° E aspect. Starting the from the top there were 4 layers of interest.

Snow Depth: 110cm
1) CT11 failure on the new/old snow interface 11cm down.
2) Buried Surface Hoar, no results, down 30cm
3) ECTP21 sudden collapse down 72cm on crust/facet combo.
4) CT21 sudden collapse at the ground on moist basal facets.

Red Flags included: Recent slab avalanches and point release on south aspects, Wind Loading, New Snow up high. No cracking or collapsing.

See attached photos for more detailed pit information

Photos & Video
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