http://news.ninemsn.com.au/glance/869276/surfing-with-a-tsunami-in-the-sky (http://news.ninemsn.com.au/glance/869276/surfing-with-a-tsunami-in-the-sky)
The clouds must be climbing/blowing over a ridge. Cool effect.
Have a look at http://en.wikipedia.org/wiki/Morning_Glory_cloud as it explains how the Morning Glory clouds are formed