4-7,8-06, Natural Avalanches

(Old Logway Canyon and Naomi Peak avalanches occurred on 4-6-06)

Heavy snow and high west winds caused some large natural avalanches in the region on Thursday, 4-6-06.  This classic crown on Scout Peak is at the top of Old Logway Canyon above the town of Mendon.

This very broad avalanche in upper White Pine Canyon naturally released during Thursday's storm.  Evidence of the avalanche was blown in, and there was about 6 inches of heavy new snow on the bed surface.  When it occurred, the wind-slab avalanche was 1 to 2' deep and more than 800' wide.  With a nice bench below, it only ran 150-250 vertical feet.

The Old Logway Canyon avalanche ran about 2500 vertical feet.  The crown at just under 9000' in elevation on a mostly east facing slope is at least 400' wide and probably about 4' deep.  Like the other recent big natural avalanches in the area, this one most likely failed on a sugary or faceted weak layer associated with the prominent February 28 rain-crust.

Tons of heavy snow and a fair amount of earth piled-up on Maple Bench below Old Logway Canyon.

Here's a look at the big pile from a distance.  (You can see the deposition cone clearly from across Cache Valley.)    The heavy pile is at least 30' deep at its apex where it stacked up on the bench at the base of the gully.

By the look of the deposition, it appears that the avalanche pushed a fair amount of wet snow and mud down the long winding gully. 

I didn't dare to head up the avalanche path since the big bowls flanking the one that avalanched are poised to run down the same constricting gully that I would have had to go up.

Here Brian gives a good idea of the scale of this broad avalanche under Naomi Peak.  Only about 1/4 of the crown is visible in this picture.  The steep slope at around 9500' faces north northeast.