Manteau neigeux

Sixmile

Rob MillspaughSwan Range
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Quick report

Cracking
widespread

The conditions felt complex, but I did not see any obvious signs of instability in my travels today, aside from some minor cracking and sensitive pit tests. 

  • Storm snow is "upside-down" with denser, cohesive slab resting above weaker snow. 
  • I found drifts of recent snow 12-18 inches deep.
  • Cracking was confined to the top 4-6 of the snowpack.
  • Slabs ranged from soft to hard. 
  • I got propagating results with easy force in the top 8" of the snowpack. 
  • Gale-force winds were blowing snow (and chunks of rain crust) above 6000', making it difficult to stand at times.
  • Wet snow was indeed a problem below the rain/snow line (5300'), but more in terms of travel as there is generally not enough snow to avalanche in this elevation band. 
  • Above 6000', I found a fresh rain crust on all aspects. Its depth varied from on the surface to 6 inches deep. 

The weather alone was good reason for me to keep my plan and terrain choices simple. 

Stubborn cracking in the top 4-6 inches.

Weather

Cloud Cover
overcast
Wind Loading
intense
Rain Elevation
5300'
Recent Snowfall
8-15
Snow Avail For Transport
moderate amounts

Rain below 5300', the trees were still dripping up to 5600'. Winds moderate with strong gusts below 5600'. Winds strong with gusts to extreme above 5600'. A couple pulses of graupel. Skies began clearing around 3:30pm.

Snowpack

Test pit at 6800' S aspect:

  • ECTP1, ECTPV down 20 cm on PP (2mm) under a rain crust, 
  • ECTN 27 x 2 down 55 cm on FC (1mm) below 12/7 crust

Test pit at 6800' N aspect:

  • ECTP5,6 down 20 cm on PP (2mm) under a rain crust
  • ECTN 22,24 down 45 cm on FC (1mm) below 12/7 crust
  • ECTN 30 down 70 cm on rounding facets (1mm) above the AR crust