Great Sand Dunes National Park
Mosca, Colorado
On the eastern side of the remote, high-mountain San Luis Valley,
between the Blanca Massif and Crestone Needle, are the
Great Sand
Dunes, the tallest sand dunes in North America. The dunes cover
approximately 39 square miles and rise to almost 750' above the valley
floor.
The dunes are the product of the wind and rain eroding the San Juan and Sangre de Cristo Mountains that ring the
San Luis Valley. They have collected here because the prevailing winds across
the valley blow in this direction and meet winds blowing in the opposite
direction. The sand drops to the valley floor and is held in place by water
flowing from the Sangre de Cristo's. So over the course of millennia, the dunes
have built up to where they are today. And tomorrow they will be different
because the wind still blows, the sand still moves and the deposits of sand
still grow.
The dunes are like continually changing sculptures. Overall, they maintain a
remarkably stable form because they are so moist throughout (from the rain and
snow). But the surface layers of sand dry and flow with the wind in
ever-changing patterns.
Great Sand Dunes National Monument became
Great Sand Dunes National
Park and Preserve on September 13, 2004, when Secretary of the Interior Gale
Norton signed a declaration making this America's 58th National Park. The Great
Sand Dunes National Park and Preserve Act of 2000 mandated the purchase of the
97,000-acre Baca Ranch to create the National Park, the Baca National Wildlife Refuge and to make
significant additions to the Rio Grande National Forest.
This acquisition occurred through the cooperation of a consortium of private,
state and federal partners, including major assistance from the Nature
Conservancy. Part of the 103,000-acre Zapata-Medano Ranch (owned and
operated by the Nature Conservancy) is included in the National Park and the
Baca National Wildlife Refuge.
Hiking to the top of the High Dune is a popular endeavor. Though it is not the
tallest dune, it appears that way from the visitor center. This hike is not done
on a trail; the hiker zigzags up the sandy dune for a 650 foot gain. Though the
hike is not easy, the view from the top of the dune is worth the effort.
The Visitor Center is open from 9:00 AM to 6:00 PM, Memorial Day to Labor
Day. Hours vary the rest of the year.