February 2, 2015

Observations – Arctic Valley

Signs of instability:

Weather:

  • Temps in the 20s with clear, sunny skies
  • Light to moderate south wind with modest snow transport on exposed terrain above ~3000′

Surface conditions:

  • Snow depth ranging from a dust on tundra to ~3′ with facet-crust combos in places where there is a “snowpack”
  • Up to ~10″ soft, powdery snow in the best spots
  • Generally 1-2″ soft powdery snow, but without much of a base beneath it
  • Hard wind slabs and exposed icy crusts in areas
  • Radiation recrystallization crust in places on solar aspects (thin, weak crust below ~2cm soft snow)

Discussion:

Southerly winds picked up early this morning through mid day at Arctic Valley resulting in modest snow transport and the development of thin, touchy wind slabs in some areas on steep leeward terrain.  Two small, D1 wind slabs were triggered while descending a steep (40+ degree) NW facing slope.  As these were fresh, they broke at the feet and (being anticipated) were manageable.  While wind slabs generally stabilize relatively quickly, those that developed today may still be reactive but a little more stubborn in the next day or two.  Be mindful of their distribution and consequences.  During this interim period before they stabilize, they may not be as predictable and manageable.  Of note with the wind slabs triggered today, the first one’s runout went over where the second one was triggered.  However, the second one was not triggered by the first running over it.  It took a jump turn on it before it released.

The debris from the two SS-ASu-D1-R1 that ran ~500′ (both crowns 10-20′ wide and 1-3″ deep) on a NW aspect:nike ws 1ws 2

Here’s a general look at snow depth around 3000′ on a NW aspect:hand pit

The average snowpack in a more blown-in area around 3500′ looks something like this:full pit 1 Gordon Lyon area 2:2:15

A look at coverage in the Gordon Lyon north bowls:n bowl cov 3 n bowl cov 2 n bowl cov 1

Plenty of sunshine and vitamin D this week as consolation for a depressingly thin snowpack and three progressively worse winters:gl soforvousav inlet

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