Observation: Summit

Location: Tenderfoot

Route & General Observations

We toured up to 2300′ on Tenderfoot. We took the standard route but were pleased to see the up-track went far skinners left along the treeline through the alders to avoid crossing the open slopes that it usually crosses. We were looking at the new snow/old snow interface and tracking the multiple layers of buried surface hoar. Poor visibility and winds kept us below treeline as well our knowledge that the 2-3′ of new snow might be sitting on buried surface hoar(BSH).

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

We ran into the party that put the skin track in the day before and they said they had experienced whumpfing while breaking trail.

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

Obscured and snowing throughout the day. 2" of new snow fell while we were in the field.
Winds were moderate with strong gusts
Temps were in the 20Fs

Snow surface

1200-2000' 4"of new snow over a rain/drizzle crust over 2' of storm snow. Crust thins with elevation gained. It is breakable even at 1200'. Ski pen= 45cm, Boot pen=80cm
2000-2300' 6-8" of new snow on stiffer wind affected snow over 2' storm snow


We dug three pits that had mixed results. There is now a significant slab over BSH. The reactivity of these buried persistent weak layers varied in our tests. We did find evidence that it could potentially be triggered by the weight of a person. We dug in fairly protected areas. Hopefully some of the surface hoar was blown away in more wind affected terrain but until we get to dig in more spots and verify that, this set-up seems fairly spooky. Buried surface hoar has really been the theme of the snowpack in Summit Lake this winter.

Pit #1. 1920', NW aspect, 30 degree slope, HS= 210 cm, Pit height=138 cm. Drizzle crust @ 24 cm below the surface. (6 mm BSH) @ 66 cm below the surface over melt-freeze crust, (6 mm BSH) @104 cm below the surface over melt-freeze crust. ECTX x 2

Pit # 2 1960', W aspect, 32 degree slope, HS=215 cm, Pit height=110 cm . Drizzle crust @ 15 cm below the surface. (6 mm BSH) @ 60 cm below surface over a melt-freeze crust CT 12 x 2 SC, ECTP 14 SC. (8 mm BSH) @ 90 cm below surface, over melt-freeze crust, CT 14 x 2 SP, ECTP 21 SP

Pit # 3, 2300' W aspect, 30 degree slope, HS =250cm, Pit height 150 cm, wind crust @ 16 cm below the surface, CT 12 RP, (6 mm BSH) over melt-freeze crust @ 75 cm below the surface, CT 12 SC, (8 mm BSH) over melt-freeze crust @ 100 cm below the surface, CT 27 SC, ECTX, PST 25/100 SP. See video

Photos & Video
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