Death Valley National Park contains several dune fields.
The most visited would be the Mesquite Dunes adjacent
to Stovepipe Wells. Other popular dunes are the Eureka
Dunes, Panamint Dunes, Saline Valley Dunes, and the
Ibex Dunes. All these dunes are formed by the accumulation
of loose sediment, namely sand-sized particles. The
source of this sediment is from erosion of rock by water,
wind, and gravity.
There are a couple of requirements for dune formation.
One of these requirements is wind. Sand is blown by
wind until it reaches an obstacle. In the case of Death
Valley, obstacles are mainly mountains! Wind doesnt
have enough energy to blow the sand-sized particles
up and over the mountains, as the wind-energy decreases
they drop their load and deposit them where we see it
today. It takes many wind storms to accumulate the amount
of sand we see in Death Valleys dune fields.
Although their movement is limited by prevailing wind
directions and mountains, individual dunes are constantly
changing shape and location. It is not uncommon to find
that footprints from a previous days hike have
been erased, cleaned by the wind.
Along with wind, another requirement is a dry climate.
Fortunately for our dunes, the average rainfall in Death
Valley is only 1.65 inches per year. Moisture would
cause sand-grained sized particles to stick together,
making it much harder for wind to move the material.