Dunes or ripples? It's all a matter of scale. Ripples in the sand on a frosty afternoon on Newburgh bar
<a rel="nofollow" class="external text" href="https://www.geograph.org.uk/profile/6287">Martyn Gorman</a>
CC BY-SA 2.0
From <a rel="nofollow" class="external text" href="https://www.geograph.org.uk/photo/631112">geograph.org.uk</a>