Observations – April 9, 2013

Front Range – Rabbit Creek Valley

Signs of Instability:

  • Numerous small natural loose snow avalanches (sluffs)
  • Small human triggered soft slab near the top of Peak 4
  • Small human triggered sluffs along the Peak 3-4 ridge
  • Two whumphs in heavily loaded areas along the Peak 3-4 ridge
  • Small shooting cracks in some moderately-heavily loaded areas


  • Mostly cloudy skies with intermittent flurries and sunny breaks (no noticeable accumulation)
  • Light N wind creating some saltation and subtle snow transport early-mid day, calm wind late afternoon
  • Mountain temperatures in the lower-upper teens

Surface Conditions:

  • Several more inches of light, dry snow (slightly more water content and smaller grained than previous storm)
  • ~6″ fresh at trailhead, 6-10″ fresh on slopes
  • Very subtle wind affect in areas
  • Some thin wind exposed areas with only a few inches of soft snow on top of the old, hard melt-freeze crust
  • Lower elevations and southerly aspects were warmed enough to moisten – a crust may ensue but is not likely to be widespread

Avalanches Concerns:

While winds have remained relatively light in this area some loading has occurred and created pockets of wind slab on south to west aspects along the Peak 3-4 ridge.  These wind slabs don’t seem to be reactive on lower angle slopes, but have not yet been tested or experimented with on higher angles.  A couple touchy soft slabs where found in typical areas, one being a steep rollover where 8-10″ of new snow appeared to lay over a thin layer of lighter density and bigger flaked snow from the previous storm that acted as a weak layer on top of the bed surface of the old melt-freeze crust.

The sun did manage to shine through at times today and warmed the snow enough to moisten it on the more southerly aspects.  Some small point releases and rollerballs occurred late in the afternoon.

From observers in the South Fork Eagle River area:

  • toured up harp mountain then skied down just below 90% gully. On the way up we noticed an apparently spontaneous slide, about 50-75 ft wide, estimated 1 ft crown slide with low energy down to gully bottom. appeared to be very soft slab with slow movement but sliding quite away. North facing slope. ~30 degrees. 3300ft. Some boarders had just ridden down adjacent slope but I can’t believe they triggered it as they were around the corner. We also heard whoompfing on several occasions. We cut a cornice without any reaction though, it was soft and ended up breaking apart. minimally wind affected snow noticed up high. multiple soft snow sloughs from point releases noticed throughout the valley.
  • long running sluffs south facing Cotton Grass and 3 Bowls

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