Winds blowing through Death Valley are slowed
here by the changing shape of the valley and
towering Tucki Mountain. The weakened winds
cannot carry their cargo of sand any further.
Quartz grains, scoured from the surrounding
mountains, compose the deposited sands. While
winds constantly shape and reshape individual
sand dunes, the dune field itself does not move.
In Death Valley, sand dunes are less common
than you might expect. Five widely separated
dune fields exist in this national park -- yet they
account for only a fraction of the total acreage.
Sand is scattered throughout the desert, but in
only a few places is it gathered by the interaction
of wind and mountains to form dunes.
Moderate winds blowing predominantly
in one direction form tranverse dunes.
Winds blowing from several directions
create non-migratory star dunes. The
development of different dune types here
indicates a complex wind flow pattern.