Observation: Turnagain

Location: Petes North

Date:
Observer:
Route & General Observations

Johnson Pass trailhead to powerline, trees, alders, and up to treeline – 2300′ – on a NW aspect.

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

Temperature 5f down low, warming to the teens up high.
Clear in the am, increasing clouds throughout the day.
Light SE wind above treeline mid-afternoon

Snow surface

10-15mm surface hoar on top of fist hard facets to treeline; this surface hoar had been disturbed by winds on more northerly aspects at treeline.

Obvious wind affect on ridge above treeline, and windslabs were present on NW to W aspects at treeline.

Ski Penetration (PS) of 20-30cm in sheltered locations, ~10cm at treeline.

Snowpack

@ 1400' in a sheltered location, 70cm of snow covered the thanksgiving rain crust, with 40cm from last weekend's storm (Fist -> 4 finger hard), 25cm from the week prior under that (1 finger), all over 10cm of 4 finger facets to the stout thanksgiving crust.

Pit #1: NW aspect, 2200', 30 degree slope, Height of Snow = 140cm
From the surface:
10mm Surface Hoar
0-20cm = Fist hard facets
20-40cm - 4 finger hard snow
40-65cm - 1 finger hard snow
65-75cm - 4 finger rounding facets
Over the very stout Thanksgiving melt freeze crust.
Pit result: ECTX.
However, a slight tilt of the column post test caused a sudden planar failure 75cm down in the rounding facets, at the interface with the Thanksgiving Crust

Pit #2: W aspect, 2200', 30 degree slope, Height of Snow = 115cm
Location chosen very close to pit #1 in a more shallow location - same general structure, with a thinner 45cm slab over the four finger facets described above.
Pit Result: ECTP 29 RP 45cm down, just below the 1 finger slab at the top of the rounding facet layer.

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.