Text Box: 2-17-07, Tony Grove Area Avalanches
             Toby Weed
 
 

Two natural avalanches are visible on the East Face of Mount Magog.  The blown-in crown under the rocks on the right occurred during Thursday night's storm, while the fresh one on the left probably happened yesterday, 2-16-07.

 

This fresh wind slab avalanche on a 40 degree east-northeast facing slope at around 9400' in elevation is around 200' wide and 1-2' deep.

 

I noticed a couple small triggered avalanches on the short northeast facing slopes above Tony Grove Lake.  If you trigger small slab avalanches like this, you know you could trigger larger ones higher up.

Seen in the distance, this fresh natural in the South Fork of High Creek Canyon in the Mount Naomi Wilderness is a much bigger and more dangerous slab avalanche.  Just by the looks of it, even from afar, I'd say it failed on a deeply buried weak layer.

Here a a broad step-down on a repeater avalanche on the north facing side of Castle Rock.  It looked like a shallow new snow wind slab overrunning the slope triggered a step-down into old, weak faceted snow.

 

A similar natural avalanche occurred nearby on the east face of Naomi Peak.  A new snow avalanche came down the steep slope above and when it overran the lower slope, the avalanche stepped down into old buried weak layers and suddenly got much bigger.

 

Even though the evidence is blown-in by Friday's wind, you can still see the deeper crowns of the lower step-downs.

 

Several times today I turned my beacon to the receive mode to check out large piles of un-inspected deposition.

 

A slab so hard I couldn't even stick my finger in it released when overloaded by a smaller avalanche on a thin weak layer consisting of large well-developed and very sugary facets.

Text Box: □
Text Box: →

 

Text Box: □