Avalanche: Tony Grove

Observer Name
Eric and Amy Flygare
Observation Date
Tuesday, December 27, 2016
Occurrence Date
Tuesday, December 27, 2016
Occurence Time
10:00am

Region:

Location Name or Route
Tony Grove
Elevation
9000
Aspect
East
Slope Angle
35
Trigger
Snowboarder
Trigger: additional info
Intentionally Triggered
Avalanche Type
Soft Slab
Avalanche Problem
Wind Slab
Weak Layer
Density Change
Depth
12"
Width
50
Comments

We rode a bunch of slopes in the Tony Grove area today looking for the best riding conditions.  We rode north through southeast facing slopes between 9300 feet down to 8000 feet.  We found everything from wind scoured slopes along ridges, wind loaded slopes in many fetch areas, and great powder conditions on lower protected slopes. 

The biggest concern of the day was wind loading.  The wind was howling from the west all day scouring many slopes (picture 1 sastrugi) and loaded up many slopes in the area.  Cornice Ridge avalanched several times in the little time we were in the general area (the second picture is one little slide on Cornice Ridge).   The slides were not big but continuous wind loading convinced us to leave rather quickly.

Even areas off the major ridgelines were receiving plenty of wind loading.    Picture 3 is of a chalky 6 inch thick wind slab just off a major ridge.  Picture 4 is of a 50 foot wide wind slab breaking as Amy carves down a short test slope.  The slab fractured in front of her but, due to the concave nature of the slope, it was trapped in place and went no further.

We moved into an area far away from the major ridgelines where we found much better riding.  Even though the riding was better we found pockets of very sensitive soft wind slabs.  The last picture shows a 30 foot wide wind slab in a somewhat protected area.  It was very slow moving and only ran 100 vert or so. 

All wind slab failures were on north through east facing slopes greater than 35 degrees

Coordinates