Persistent Slab Avalanches on Lake Fork

Location Name: 
Lake Fork Area
Williams Lake Area
Date and time of observation: 
Fri, 01/12/2018 - 11:47
Location Map: 
United States
36° 33' 10.0152" N, 105° 26' 31.0956" W

Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
Terrain Trap

Observation made by: Forecaster
Snowpit Observations
More detailed information about the snowpack: 

Headed up to Lake Fork peak to see what was going on there on North aspects.  This zone has held on to less snow and was a safe option to access smaller and steep test slopes.  Every slope I touched that was holding snow collapsed with shooting cracks.  Several slopes produced small persistent slab avalanches.  Some slopes had been scoured and others had 4 finger hard wind slab.  Key takeaways from the day are that we have an incredibly weak snowpack where snow does exist.  We can get collapsing and shooting cracks but we need steep slopes (>37 degrees) to produce avalanches.  The bed surface makes a big difference, as we have a lot of anchors with our boulders in our depth hoar at the bottom.  Slopes that were able to produce avalanches had a slab from previous wind loading that was over depth hoar.  You'll be able to trigger a collapse from below, as several slopes from triggering them 100' below.  With all this instability, we still don't have much of a snowpack.  It's a lot of work to get there and we don't have great connected slabs which limits the propagation potential.  Where we do hold snow on higher elevation on North aspects, it is suspect as even a small ride would be incredibly painful. 

Photo 1:  A small avalanche (D .5) that we triggered 100' below the crown

Photo 2: A closer look at the crown with the weak faceted snow below a 1 finger hard slab

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Weather Observations
Blowing Snow: 
Cloud Cover: 
75% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Air temperature trend: 
Wind Direction: 
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Light flurries started around noon.  I don't anticipate any accumulation during the day.