Erg is a word.
It might be a good word to describe what is going on in Libya, as it sounds so close to "ugh."
An 'erg' is, perhaps not surprisingly, the Arabic word for dune field—what we stereotypically think of as a desert—a barren wasteland extending as far as the eye can see covered by undulating, sinuous lines of sand mountains. This is what much of southern Libya looks like. It's the Sahara.
Above we see Erg Chebbi in Morocco where the highest dunes reach 500 feet.
So alien are ergs that there are ergs on alien worlds—Venus, Mars, and Titan. Here is the 130-mile wide Kaiser Crater erg on Mars:
It looks like the ear of a purple frog.