tail wave

After a river plunges over the rocky debris of a rapid, it blasts out from the constriction and finishes in a series of high-momentum tail waves. The waves stand like glassy dunes, stationary in form even as the river flows through them toward stillness again. When their foamy crests roll over and slide partway down their face, like the archetypal wave in a Katsushika Hokusai woodblock print, they are sometimes known as curlers.

Ellen Meloy