Portraits of Wildflowers

Perspectives on Nature Photography

Posts Tagged ‘Great Sand Dunes National Park

Monday mountains 3

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On the many Mondays in January you’re seeing mountains.

I rarely use a polarizer, but I did to convey the drama of clouds over the Rocky Mountains viewed from Great Sand Dunes National Park in Colorado on June 8, 2017.

P.S. As Tom noted in a comment below, this sub-range of the Rocky Mountains is known as the Sangre de Cristo.

© 2018 Steven Schwartzman

Written by Steve Schwartzman

January 15, 2018 at 4:55 AM

Flowing water adjacent to the Great Sand Dunes

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I don’t know about you, but when I think of water and sand dunes together I think about dunes on the seacoast. When I visited Te Paki in New Zealand in February, I was surprised to find a stream separating the parking lot from the dunes. The same thing is true in Great Sand Dunes National Park, where people who want to walk to the dunes from the parking lots have to cross Medano Creek (médano is a Spanish word for ‘dune’). What’s strange about Medano Creek is that it pulses. The phenomenon is known as surge flow, and here’s what the website of Great Sand Dunes National Park says about it:

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. In spring and early summer, these elements combine to make waves at Great Sand Dunes. As water flows across sand, sand dams or antidunes form on the creekbed, gathering water. When the water pressure is too great, the dams break, sending down a wave about every 20 seconds. In wet years, waves can surge up to a foot high!

I noticed the phenomenon when I went to take pictures of sand patterns in Medano Creek. No sooner would I compose and take a few photographs, than a “wave” of water would flow downstream and obscure my subject. The picture above shows the shallow regular flow of Medano Creek; the picture below shows a moment of surge flow.

© 2017 Steven Schwartzman

Written by Steve Schwartzman

June 27, 2017 at 4:48 AM

Great Sand Dunes

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Great Sand Dunes was the third of the four national parks we visited on our recent trip. At 720 feet, these are the tallest sand dunes in North America. In addition to that, they sit at an altitude of about a mile and a half, so when we were there on June 8th we took pity on our poor lungs and decided not to trudge up these mountains of sand (unlike the Te Paki Dunes that are just above sea level and that we’d climbed in February).

The dunes are so high that when you’re close you can’t see the mountains beyond them. The picture below gives you a broader view, made more dramatic through the use of a polarizer to add extra definition to the clouds and greater contrast in the sky.

© 2017 Steven Schwartzman

Written by Steve Schwartzman

June 26, 2017 at 5:00 AM

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