Phenomenon near Australia

The cloud appeared at sunset off the coast of Onslow, in the Pilbara region in West Australia's northwest, where residents are bracing for Cyclone Narelle. Picture: Levi Cooper, The Bureau of Meteorology said the phenomenon was created as wind and rain caused the storm to dump sand and dust it had picked while passing over Onslow. http://www.theaustralian.com.au/news/nation/gallery-e6frg6nf-1226551852435?page=5