Observation: Hatcher Pass

Location: Eldorado Bowl Lowers

Route & General Observations

Toured to lower Eldorado Bowl rollers to investigate recent wind slab depth and sensitivity, as well as basal weak layer instability.









Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Observer Comments

Other a couple recent small D1 wind slab avalanches and evidence of older avalanches which failed on the October basal persistent weak layer, I did not see new avalanches today.

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

Broken skies with patches of sunlight and good visibility. Deteriorating cloud covered ended our tour early in felt light and overcast skies around 2 pm.
The weather front brought warmer temperatures making it feel balmy compared to the weekend and early week.
Upper elevations peaks had pluming and flagging from strong winds transporting abudant low density snow available for transport (AST).

Snow surface

On the surface wind broken snow crystals from wind scouring and saltation. This was sitting on a 1F recently deposited 3" wind crust sitting over weaker partially settled snow. See snow pit.


Recent strong winds and wind slabs:
Recent winds transported snow to the Southern half of the compass on 11/20 which shifted today to the norther half of the compass as a weather system approached. Wind slabs exist on all aspects and cross loaded features. These were unreactive, with no cracking or collapsing and instability tests did not show propagation on this interface. Wind slabs sitting on non-persistent grains appear to have bonded well. Most of the wind crust was breakable and unsupoprtive. Occasionally I encountered a short 10' section of supportable crust. I only made it to 3700' today and anticipate the crust/slab to be much thicker and supportive at upper elevations. I theorize that wind slabs could be as thick as 10 inches at upper elevations on leeward aspects.

Old basal Persistent Slab:
This is my main concern within the snowpack and the same layer that produced all the recent large avalanches including the remotely triggered avalanches. See recent observations.
Today's instability testing revealed propagation on basal facets in ECT, PST and CT, and this layer remains my primary concern. Any avalanche triggered on this layer has the dual potential to widely propagate and fail at the ground producing large avalanches.

Photos & Video
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