I love this place!! I spent a couple of hours here and wish I had had more time, but I had a long drive to my campground and did not want to get there after dark. Actually, I have never driven my rig in the dark and having to back into a narrow spot and not run over the electric post and water spigot in the pitch dark does not appeal to me.
I have poor internet and am in a hurry as I am posting from a Walmart parking lot because internet is non-existant in my isolated campground. (More tomorrow on that and Carlesbad Caverns.)
Driving into the dune area:
It is a long story, but this lake, fed by underground streams from mineral deposits in the mountains is the source of all the blowing sand and the dunes themselves.
In the heart of the dunes and a picnic area:
All plants on the dunes start their lives in between the dunes. As the dunes advance, they grow longer stems, so the yucca on the dune is really 30' taller than the one on the level ground. When the sand blows away and the dune moves, the one with the long stem will fall over!