Alluvial Fans in Death Valley
Photos by Karen S. Bartels, Ph.D.  March 2003.
On the way to Racetrack Valley, via a very bumpy gravel road!  The tan colored area in the center of the photo is Racetrack Playa.  View is from the northwest.
Walking out onto the Playa in search of racetrack rocks.  Notice the small mudcracks on the dry playa surface. 
It's a bit of a walk!
Close-up view of mudcracks.  Width of photo is 12 inches.
Aha!  Racetrack rocks! 

It looks as though these fairly large rocks (the one on the left is 10" x 6" x 3") plow their way across the playa surface when it is wet.

No one has ever seen one of these rocks move.

 

High winds come into this valley from between the low hills in the center of the photo.  Geologists hypothesize that high wind shear in this area is responsible for moving rocks when the playa is wet. 

The racetrack rock from the previous photo is slightly below and to the right of center. 

Many tracks!
Some rocks change direction in a zig zag fashion.  The black object in the photo is a pocket knife that is 4 inches long.
View from the southern end of the playa looking north. 

Such a beautiful day!