Observation: Turnagain

Location: Cornbiscuit and Superbowl

Date:

February 16, 2016 8:20pm

Observer:

J-Bloom/ Thamm Professional

Route & General Observations

Toured standard Cornbiscuit up-track, skied Cornbiscuit N Chute #3 and toured up Superbowl. Our intent was to check out the human triggered slides in Gold Pan yesterday. Due to a binding malfunction we had to turn around before getting there.

We did not get to dig a fracture line profile. However, after digging 3 pits in the area we suspect that it was sun/warm temps affecting the slab over the 40-50cm deep weak interface that was reactive in our pits (see below).

Observers today noted natural avalanches from yesterday on similar aspects and elevations.

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

Cornice fall that was observed yesterday on Magnum as well as cornice triggered slabs from cornice falls farther east along the Magnum ridge. Observed minimal roller ball activity later in the afternoon. The temperatures stayed cooler today in contrast to yesterday's afternoon spike.

Weather & Snow Characteristics

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

Weather

Clear with developing valley fog mid day.
Temps in the low 20's at @3000'
Light westerly winds

Snow surface

1000-1350' rain crust with pockets of small surface hoar (SH)
1350-1800' rain crust covered by 2-4" of settled storm snow that is starting to facet with SH, moist snow below the crust
1800'-2550' rain crust that disappears @ 2250. 4-6" settled storm snow with SH, moist snow trending drier with elevation below the crust
2550' -3650' variety of surfaces, 4-6" settled storm snow with SH or wind crust with SH or wind slab, pit @ 3300' SW aspect had a mini MF crust below the surface hoar

Snowpack

Dug in 3 locations
Pit # 1 @ 3300' SW aspect 36 degree slope, HS >300cm, Pit depth 135. Surface hoar and mini MF crust at the surface over 10 cm of dry snow. Test results @ 23 cm CT 15, RP x 3, ECTP 16 RP. @ 45 cm CT 22 RP, ECTP 23 RP. Both failed at hardness changes. Failure @ 45 cm was decomposing precip particles. the original stellar forms were still evident. This had a slightly larger grain size than above and below. It was 4F below 1F over P. I did not find any evidence of any old sun crusts. Air temp -6 C, surface temp -6.5 C, just below crust -5C.

Pit # 2 @ 3335' N aspect, 27 degrees, HS > 300 cm, pit depth 150cm. Similar results test @20 cm ECTP 16 RP, ETN 15. @ 40 ECTP 19 RP, ECTP 23 RP. Same grain id. @ 40 cm interface, decomposing precip particles and hardness differences, less resistant snow sandwiched between harder snow.

Pit # 3 @3500' W aspect, 35 degree slope, HS >300 cm, pit depth 150 cm. This was adjacent to the pit from party that submitted the Gold pan observation yesterday that described 5mm buried surface hoar 50 cm down in Super Bowl on up-track. We found the layer of buried surface hoar that was mixed with well preserved stellars. ECTP 19 RP and ECTP 24 RP at this layer, same hardness profile.

Photos & Video

Please upload photos below. Maximum of 5 megabytes per image. Click here for help on resizing images. If you are having trouble uploading please email images separately to staff.