Great Sand Dunes National Park.
Home of the largest sight of "Surge Flow" in North America, created by a phenomenon called “Antidunes” this is where the sand from the Dunes builds up as an underwater damn and when enough pressure behind it has formed the damn bursts and can create wakes as high as one foot.
At the Great Sand Dunes NP this occurrence happens approximately ever 15 to 30 seconds year round. An interesting sight to be seen and also very fun to play in on a hot summer day.
Spring and Summer are the best times to view this phenomenon.