Upper Bunchgrass 1-27-06

White Pine Knob + Chicken Hill

On 1-27-06, I triggered a number of small soft slab avalanches consisting of new snow in upper Bunchgrass Canyon.  The small slabs of light wind-drifted new snow were quite sensitive to my weight, and I easily triggered avalanches simply by walking along the ridge-tops.  This is a view of the summit of Chicken Hill from the southeast.  The avalanches are on an east facing slope.

I triggered several ridge-top slabs on north facing slopes near the ~9000' summit of White Pine Knob.  The small avalanches were around a foot deep and generally 30-50' wide, running on weak frost or surface hoar crystals. During last week's cold and clear weather, weak snow developed on the snow surface on lots of slopes and was then buried by today's snowstorm.

The foot-deep very soft slabs were manageable today.  The snow would have just slid harmlessly past you in most cases.  They can be dangerous however, if you get swept off a cliff or slammed into a tree.

These slabs broke right at the old-new snow interface on well-preserved frost crystals or surface hoar.  Yesterday's weak surface snow may cause persistent problems in the future on slopes where it was buried intact and preserved today.

A couple of these small avalanches ran pretty far.  This one, which was about 40' wide, ran over a steep roll-off out of view.  It could have run several hundred vertical feet down the 1000'+ steep north face of White Pine Knob.

You have to watch out for what is below you in the fall-line.  This small avalanche ran right through some thick trees.

This foot-deep avalanche in north facing "Check Your Pants" was about 100' wide.  The avalanche ran 300 to 400 vertical feet stopping on a bench at the bottom of a popular ski run.

The slope cracked with my presence above and slid as a unit.  I'd say conditions were pretty sensitive.  Here's a view of the eastern edge.

The small slabs I triggered from the ridge on Chicken Hill ran to the flat slope below.  These were only about 6 to 8 inches deep.  If a bit of wind picks up before or during tomorrow's snowstorm, resulting avalanches could be significantly more dangerous.