360 View of White Sands National Monument.  The endless sea of white sand dunes and the Sacramento Mountains of Southern New Mexico are in full view.

Before there was an actual 360 Degree Camera, there was me with a small video cam physically turning 360 degrees until my head would spin and I’d nearly fall to the ground.  Visualise this.  True story and this is how I captured the video seen in this post.

By now, everyone knows the affection I have for White Sands.  Now with more photographic and video armoury in my caché, I’ll return to this great sand dune area for updates.

In the meantime, have you ever wondered how the white sand dunes move?

According to the National Park Service –
Sand can only be moved by strong, steady winds. The air must be moving at least 17 miles per hour to be able to pick up sand grains. In the Tularosa Basin, it is primarily between February and April that the winds are strong enough. These winds are called unidirectional winds because they always move in the same direction, from the southwest to the northeast. As the wind blows, it pushes the sand ahead of it, so individual dunes are slowly moving to the northeast.

Sand is not as easy to move as you might think. Even very strong winds can’t lift the sand any higher than three feet above the ground. As the wind blows, it lifts small sand grains a few inches off the ground, then drops them. When they hit the ground, they bump into other sand grains and cause them to jump up and be caught by the wind. It’s almost as if the sand is playing leap-frog, jumping and bumping along. This kind of jumping movement is called saltation. You can see this kind of movement on the windward side of the dune, or the side facing the oncoming wind. But what about the leeward side of the dune, protected from blowing wind? What causes the sand to move on that side?

As the tiny sand grains slowly work their way up the windward dune face, they finally reach the crest or top of the dune. They fall over the crest and start to pile up because they are protected from the wind. Now gravity steps in to move the dune. As more and more sand grains pile up, the angle of the leeward face becomes steeper and steeper. A pile of loose material, like sand, can only hold a slope of about 34 degrees. When the slope gets greater than 34 degrees, gravity pulls the loose sand down. Small avalanches occur. The sand might run down the leeward face like a waterfall, or the whole side might slip at once. When the entire face of the dune slips, it’s called slumping.

How fast a sand dune moves depends on a number of things. Of course, the speed of the wind is a big factor. A wind that is blowing 45 miles per hour will move more sand than at 17 miles per hour. The size of the dune is also important. Smaller dunes with less sand move much more quickly than large ones. The vegetation also plays an important role. The dunes get caught on the plants that grow in the basin, and that slows them down.

There are 4 types of dunes at White Sands National Monument. The first ones to form, the “baby” dunes, are called embryonic dunes. They are usually not more than 20 feet. high, and speed along the basin floor as much as 40 feet a year. Transverse dunes form long ridges of sand and can be very tall. They move much more slowly – usually between 8 to 12 feet a year. Barchan dunes are crescent-shaped. This sand dune looks like a new moon. The arms or horns of the barchan dune always point in the direction the wind is blowing. Barchan dunes are also very large and move between 8 and 12 feet per year. The last type is called a parabolic dune and looks like an inside-out barchan dune. The movement of this dune has been slowed down by vegetation, and rarely moves more than 5 feet per year.

Obviously, I’ve visited White Sands often.  What strikes me most is the dunes are never the same each time I’m there.  The power of nature is awe-inspiring.

Map Showing The Location of White Sands National Monument ::

 

Destination:  White Sands, New Mexico, USA

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