this is wonderful and though some types of images are done a bit frequently this is the first for this specific moment and scene and I am glad you did it...
This is the first time I've ever really tried a 'dunes 'n' grass' shot. I'm aware it's a well-worn kinda shot and was reluctant to head down that track! It was really the shapes that attracted me to this picture, and the wonderful stormy light helped too.
Dan, see http://www.dr5.com for process used. I used Ilford SFX, spot metered for the mid-tones and used a 0.6 ND Grad to ensure the wonderfully stormy sky had detail. If you want any more info or advice on the dr5 process, feel free to PM me.