Observation: Turnagain

Location: Magnum

Date:
Observer:
Route & General Observations

We toured up PMS bowl and dug pits at 1570′ and 3000′ on our way up. We skied the lower Cornbiscuit meadow on our way out. The snow surface was variable, with a 2-4″ of soft snow on Magnum, and more punchy wind-drifted snow on Cornbiscuit. Looking around the pass from the ridge, it was obvious that some areas had seen a lot of wind lately, while others have dodged the wind bullet.

 

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

We were able to get some shooting cracks while stomping on fresh wind drifts just below the Magnum ridgeline. They were propagating out 5-10', and the slab was only 2-4" thick.

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

Southerly winds gradually increased through the day. There was a very slight breeze when we dug our first pits (about 11:30), and sustained moderate winds by the time we were heading out (about 3:00). Skies were mostly cloudy, and there were a few windows where the sun poked out. Air temp was 15 F at 1500' and 9 F at 3000.

Snow surface

Most of the south face of Magnum had 2-3" soft snow at the surface, which had not yet been moved around by recent winds. The west face had some wind slabs, and some scoured surfaces. The south face of Sunburst looks like it has been hit hard by the winds, with some spots scoured down to the ground, and plenty of anti-tracks across the slope. The west face of Cornbiscuit had similar wind effect to the west face of Magnum.

Snowpack

Pit 1: El. 1570', W aspect
We dug on a wind-exposed slope that had a thin wind skin on the surface. There was a weak layer of decomposing stellars and near-surface facets about 10" deep that was not propagating in stability tests (ECTN 10). We also found a thin crust about 50 cm deep that had facets right below it. This layer did not propagate with a normal ECT, but it did propagate with a few extra hard bonus taps.

Pit 2: El. 3000, SW aspect (more details in attached snowpilot profile)
We found a weak layer of stellars and near-surface facets about 8" deep, and a layer of buried surface hoar just over a foot deep. Neither layer propagated in stability tests (ECTN3, ECTN8 for the upper layer; ECTN21, ECTN18 for the surface hoar).

We dug one more quick pit on our way out at 1750' on a NW aspect on Cornbiscuit, and could not find the 1/28 surface hoar in that pit either.

Photos & Video
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