Video of river surge flow in Medano Creek at Great Sand Dunes National Park


Staff member
River surge flow is waves that naturally occur. From the NPS website, "This is one of the few places in the world where one can experience surge flow, a stream flowing in rhythmic waves on sand. Three elements are needed to produce the phenomenon: a relatively steep gradient to give the stream a high velocity; a smooth, mobile creekbed with little resistance; and sufficient water to create surges".

It's such a unique thing to see that I probably stood and watch it for an hour.