March 1, 2017

Observations

Front Range: Rabbit Creek

Route:

  • Skinned up Peak 3 gully and over to top of Peak 3.5 along ridge at 4000′ elevation band.

Obvious signs of instability (red flags):

  • Active wind loading from northerly winds observed early in the day from town (primarily appeared to be loading SW aspects).  Active wind loading by 7pm on S aspects. Avalanche from a few days ago below cliff band above Hidden Lake (SW aspect Hidden Peak – see map and photos below) visible from our location.  This avalanche was first reported to the AAC on 2/28/17.  Suspected natural trigger from recent northerly winds loading this SW aspect, or possibly from a human snowmobile trigger.  Likely HS-D2.5-R3.

Weather:

  • Clear, temps in upper single digits, wind started out light from the North and picked up to 15 mph by 7pm.

Surface conditions:

  • Variable: wind deposited snow over hard, supportable windboard. On S and E aspects: 1/8″ sun crust was present above ~3000′.

Snowpack:

We dug one pit in the Peak 3.5 gully (yellow diamond on map). Elevation ~4000′. HS 85cm. West aspect. 27 degree slope. Pit location was near ridgetop. See pit profile below. Results: ECTP14 SP down 35cm on laid-over buried surface hoar. Also ECTP24 SC down 70cm in the middle of the basal weak layer (advanced facets/depth hoar).