Weather

Virginia Lakes Area - Signs of Instability

Steve Mace and Clancy NelsonEastside Region
View on map
Observation photo 1Observation photo 2Observation photo 3Observation photo 4Observation photo 5Observation photo 6Observation photo 7Observation photo 8Observation photo 9

Quick report

Cracking
isolated
Collapsing
specific

We went for a tour in the Virginia lakes area today to survey the area post-storm and to get a sense of current instabilities. 

  • Our recent storm systems over the last week have greatly improved coverage in the area.
  • Intermittent snow showers continued throughout the day, with periodic glimpses of blue skies and waning snowfall rates.
  • We observed several audible collapses while climbing a sparsely treed NE slope between 9,000' and 11,000'.  These collapses were associated with shooting cracks up to 20' in length in a few locations. 
  • Recent wind deposits were reactive, moving towards stubborn on test slopes near treeline. We observed deposits from 4" - 15" thick. 
  • Wind transport was impressive in the alpine today up and down the range. We were sure to avoid wind-loaded slopes capable of producing avalanches over size 1 in size. 
  • Digging in on a north aspect around 9800', we found about 50 cm of new snow since 2/4. There was a series of crust layers from the Storm on 2/1, and about 1 meter of faceted snow below. Test results found propagation just above the rain crusts on a thin layer of buried near-surface facets.
    • See profile for more details
-Localized collapsing near and below treeline- -Reactive wind deposits 10-50 cm thick found on small test slopes near treeline- -Copious amounts of blowing snow and wind loading observed in the alpine-

Weather

Air Temp
27
Cloud Cover
broken
Wind Loading
moderate
Recent Snowfall
50
Snow Avail For Transport
large amounts

Extreme southwest winds were driving intense wind-loading near and above treeline across the range for most of the day. Skies were largely overcast, with intermittent snowfall throughout the day.