Every Year the Snow Melt Creates an Amazing Natural Waterslide at Great Sand Dunes National Park

Late May and early June are the best times to experience Medano Creek's surge flow.

Great Sand Dunes National Park
Photo: Getty Images

For a few months each year, a natural phenomenon creates a rare waterslide-like effect at Medano Creek, located in Colorado's Great Sand Dunes National Park and Preserve.

Medano Creek starts in the snowfields of the nearby Sangre de Cristo Mountains, melting into Medano Lake and flowing around the basin of the area's dunes, where it turns into a wide and shallow stream.

The phenomenon, known as surge flow, occurs when snow at the peaks melts and trickles down to the sand ridges, creating underwater ridges in the sand that build up and break every 20 seconds to produce waves in the creek, as park representatives explain in a video. Think of it like mini natural rapids, which are best experienced on an inner tube.

While the peak flow of the phenomenon, where the creek experiences a flow at speeds of some 40 cubic feet per second, typically occurs in late May or early June, a wet and cold winter season can lead to a slower melting rate and delayed peak date.

Check the national park's website for up-to-date information on the creek's current conditions before you go to avoid disappointment — at certain times of the year, including the summer months, the flow can be down to a trickle.

Medano Creek, which is often referred to as "Colorado's natural beach," is surrounded by the soaring dunes the area is known for and is open for activities including surfing, wading, skimboarding, and floating when water levels rise during surge flow season.

Families and visitors of all ages can often be seen setting up tents where they'll enjoy outdoor picnics and sandcastle building after taking a dip or riding an inner tube along the waves in Medano Creek, creating a relaxing escape to enjoy after exploring the rest of the national park's forests, alpine lakes, and towering dunes.

Visitors will also want to note that June is often a crowded time to visit the park, with long lines of traffic. For that reason, park representatives recommend visiting on weekdays vs. over the weekend.

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