[Umpqua Dunes on the John Dellenback Trail in the Oregon Dunes National Recreation Area.]
As the sea level changed over the last Ice Ages, the ocean waves cut a terrace between what is now the mouth of the Coos River and just north of the mouth of the Siuslaw River (near Florence). Prevailing currents and winds piled sand up on that marine terrace, sculpting it to create the suite of habitats of the Oregon Dunes.
[Oregon Dunes National Recreation Area, USFS]
Wind-blown sand is the essence of the dunes, building, sculpting, and decorating these iconic structures. The wind also blows sand to cover forests and blows sand to uncover wetlands. Over time, the various habitats—forests, wetlands, shrublands, and meadows—change with the movement of the sand.
Sand rarely travels far suspended in the wind, however. Most sand movement is by “creep and roll” and by “saltation”—dancing along the surface.
[landforms.eu/lothian]
So, what does moving sand look like close up? Click here to find out!
As the Oregon Dunes developed, the blowing sand constricted some of the streams along the coast, creating a series of freshwater lakes.
[Oregon Dunes National Recreation Area, USFS]
Click here to arrange for your personal discovery of the Oregon Dunes. (permitted by the ODNRA, Siuslaw National Forest, USFS)