parabolic dune

A dune with the crescent swoop of a parabola whose tapering arms point into the wind, not away from it, as happens with the barchan dune. Parabolic dunes are more common near beaches and in areas with moderate accumulations of sand; barchan dunes, much less vegetated, are found in rockier environments. In their natural state, parabolic dunes advance more slowly than barchan dunes but overwhelm whatever is in their path; barchan dunes tend to lose their shape against an obstacle. In Dune Country, Janice Emily Bowers offers an explanation for the slower movement of a parabolic dune: “[They] are well anchored with plants: Mormon tea, rosemary mint, squawbush, soaptree yucca, fourwing saltbush, crucifixion thorn, Rio Grande cottonwood, rubber rabbitbrush, claret cups hedgehog, and plains prickly pear.” Michigan’s Sleeping Bear Dunes, on the eastern shore of Lake Michigan, harbors many parabolic dunes among its striking array of perched dunes.

D. J. Waldie