Oregon National Dunes
Oregon National Dunes is the largest area of coastal sand dunes in North America, extending along the coast of Oregon between the Sislaw and Coos rivers. These dunes have been created through the combined effects of coastal erosion and wind transport of sand over millions of years and extend up to 2 miles (4 km) inland, rising to 500 ft (150 m) above sea level. A continuum of dry and wet conditions extends through the dune area. Close to the beach are low foredunes of sand and driftwood stabilized by marram grass. Behind these are hummocks where sand collects around vegetation. Water accumulates around the hummocks seasonally, giving them the appearance of floating islands. Behind the hummocks are further distinct regions, ranging from densely vegetated areas that become marshlike in winter to completely barren, wind-sculpted high dunes. The dunes are a popular location for various recreational activities, including riding all-terrain vehicles (ATVs) and dune buggies.
The use of dune buggies and ATVs, especially when raced in large numbers, may destroy the grass on the dunes, making them susceptible to wind scour. This may in turn lead to self-propagating breaches in the dune ridges. To protect the dunes, ATV usage is restricted.