Widespread Natural Avalanches 1-10/11-2005

                                                                               (Steep Hollow Area 1-15-05)            

           Logan avalanche forecaster, Dave Kikkert photographs the crown-face of a large natural hard slab avalanche in upper Steep Hollow.

         These twin avalanches probably occurred simultaneously on 1-11-05.  The slides are low, near mid-slope on steep north northeast slopes at about 9300 feet in elevation.

 This view of Dave poking the crown of the southern twin shows areas where the avalanche stepped down into deeper weak layers. The upper weak layer is associated with the prominent December 10th rain crust, but the avalanche stepped down into sugary snow that fell before Thanksgiving.

Here's another view of the doppelganger avalanches just south of Double Top Peak in upper Steep Hollow near the Idaho Border.  Both avalanches are about 6 feet deep and 400 feet wide.  The huge piles of debris ran way out in the flats and over a bench.   Had I been in this meadow before the avalanches, I might have mistakenly thought I was a safe distance away from the steep slopes that avalanched.                       

Even though we were exposed to possible hang-fire, we felt comfortable looking at the crown since the snow above us had stayed in place for four previous days since the avalanche.

In Steep Hollow we saw evidence of large natural avalanches facing just about every direction.  This large mid-slope avalanche occurred on a steep southeast facing slope.

          We used this recent avalanche on a steep slope in tight north facing trees as a safe ascent route to gain the upper Steam Mill Ridge.  This is a good example of an avalanche failing on large weak sugary crystals at the bottom of the snowpack, or depth hoar.  Up until the heavy snowfalls of early January the snowpack on this slope was quite shallow.  Because of  the resulting strong temperature gradients, a very weak basal layer developed.

Big natural avalanches were prevalent in the area on steep northeast facing slopes like this one.  Unfortunately, lots of similar slopes didn't avalanche, and some could be hanging in a delicate balance, just needing a little sudden additional weight to produce a dangerous hard slab avalanche.

The big, southwest face of Double Top Peak sported this very broad crown.  Many, but notably not all of the big avalanche paths in the Mount Naomi Wilderness avalanched during the January 10th-11th natural cycle.