When readers started forwarding these photographs to us just after Hurricane Katrina struck the Gulf Coast in August 2005, our first thought was that the scenes depicted in these images didn't look like either a hurricane or the Gulf Coast. Our second thought was that we've seen these pictures before many times.
Indeed, these pictures are apparently all-purpose storm photos, trotted out on a near monthly basis and retitled to correspond to the latest large weather phenomenon. These photographs have now been circulated as depicting:
Australian tornadoes, May 2005
Severe storms in southern Alberta, July 2005
Severe storms and tornadoes in Ontario, August 2005
Hurricane Katrina in the Gulf Coast, August 2005
These images are actually photographs of tornadoes taken by storm chaser Mike Hollingshead in southwest Iowa in late spring 2004. Most of them are viewable on the 2004 Digital Photos section of his web site (scroll about halfway down the page).