Observation: Turnagain

Location: Sunburst

Route & General Observations

Standard route up West ridge to 3100′.

Red Flags
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Observer Comments

Above freezing temps below 2500', but didn't see any other signs of instability.

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

Very light rain
42F at sea level, 36F at 1000', 28F at sunburst Wx station
Light East winds w sone gust to ~20 mph
Rain/snow line was around 2500'

Snow surface

Thin rain crust from the road level to 2500'- zipper crust
This rain crust is sitting on 1" of wet new snow below 1600'.
Above 2000' there is 2" of dry new snow beneath the moist rain crust. This made for very gloppy skinning conditions.

Near the ridge ~2400' the snow was very wind affected. Wind loading along the South side of the ridge and old anti tracks on windward features. Small isolated cracking along a test slope feature, but no shooting crack.

Small wind balls were present below 2800'


We focused on the new snow/old snow interface and dug numerous hand pits. Slab was soft and variable between 1-8". We didn't find any buried surface hoar in our hand pits or test pits, but near surface facets were present below the new snow in most places. Shovel tilts tests failed easily on this layer. Other tests were not as affective due to how thin and soft the slab was.

We dug two pits at 2300', HS=140cm and HS=110cm. Structure was right right side up and tests were unremarkable. One CT failed 45cm below the surface on a slight density change on 0.5mm facets. We also found 1mm rounding facets down 95cm, but no test failed on this layer. The crust near the ground was P hard with 1F layer of large (2mm) melt forms, no striations present. Crust/ground interface was moist. See photo.

We dug a quick test pit on a West aspect at 3100', HS=130cm, pit height ~70cm. Compression test failed easily on new/snow old snow interface down 8cm on tiny near surface facets. See photo diagram. We also had one moderate failure in a Compression Test 25cm below the surface on a density change within an older snow layers. The grains were a mix of decomposing fragments and tiny facets .25-0.5mm.

Photos & Video
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