The difference is a matter of size: ripples are small ridges of sand with a height (amplitude) typically less than 4 cm and wave lengths (crest to crest) less than 60 cm, while dunes have the same ...

A unique combination of sand and snow transformed a Colorado national park into an otherworldly winter wonderland, a stunning ...

Sand deposition, accretion ... symmetrical to asymmetrical dune ridges. The morphology of foredunes is varied but they can be classified into three main types: incipient foredunes, established ...

Inland, sand dunes rise almost 200 feet in a series of ridges, blowouts and valleys, while wetlands fill depressions between dune ridges. The park is home to over 1,100 flowering plant species and ...

This story appears in the November 2012 issue of National Geographic magazine. I got my first lesson in the physics of sand dunes in 1998 on an expedition into the Sahara. In order to take aerial ...

Primary vegetation gives stability to the sand dune which, in turn, traps sand. Wind is then deflected over the ridge and vegetation, creating shelter for larger plants to grow and establish.

A unique combination of sand and snow transformed a Colorado ... The photo shows morning light illuminating “a ridge of snowy, undulating dunes” while other ridges are shadowed in soft ...