PERMITTED USE: This image may be downloaded or is otherwise provided at no charge for one-time use for coverage or promotion of National Geographic magazine dated September 2012 and exclusively in conjunction thereof. No copying, distribution or archiving permitted. Sublicensing, sale or resale is prohibited. REQUIRED CREDIT AND CAPTION: All image uses must bear the copyright notice and be properly credited to the relevant photographer, as shown in this metadata, and must be accompanied by a caption, which makes reference to NGM. Any uses in which the image appears without proper copyright notice, photographer credit and a caption referencing NGM are subject to paid licensing. You MUST follow these requirements if using the images: 1. Include mandatory photo credit with each image © photographer name provided with caption below 2. Show the September cover of National Geographic somewhere in the post (credit: National Geographic) 3. Provide a prominent link to: http://ngm.nationalgeographic.com/2012/09/extreme-weather/extreme-weather-photography 4. Mention that the images are "from the September edition of National Geographic magazine for iPad, available on the App Store." OR when using the print edition cover mention that the image is "in the September 2012 issue of National Geographic magazine, on newsstands August 28." Photograph by Scott Olson, Getty Images MISSISSIPPI Fortified by a levee, a house near Vicksburg survives a Yazoo River flood in May 2011. Snowmelt and intense rains—eight times as much rainfall as usual in parts of the Mississippi River watershed—triggered floods that caused three to four billion dollars in damages.

PERMITTED USE: This image may be downloaded or is otherwise provided at no charge for one-time use for coverage or promotion of National Geographic magazine dated September 2012 and exclusively in conjunction thereof. No copying, distribution or archiving permitted. Sublicensing, sale or resale is prohibited. REQUIRED CREDIT AND CAPTION: All image uses must bear the copyright notice and be properly credited to the relevant photographer, as shown in this metadata, and must be accompanied by a caption, which makes reference to NGM. Any uses in which the image appears without proper copyright notice, photographer credit and a caption referencing NGM are subject to paid licensing. You MUST follow these requirements if using the images: 1. Include mandatory photo credit with each image © photographer name provided with caption below 2. Show the September cover of National Geographic somewhere in the post (credit: National Geographic) 3. Provide a prominent link to: http://ngm.nationalgeographic.com/2012/09/extreme-weather/extreme-weather-photography 4. Mention that the images are "from the September edition of National Geographic magazine for iPad, available on the App Store." OR when using the print edition cover mention that the image is "in the September 2012 issue of National Geographic magazine, on newsstands August 28." Photograph by Daniel Bryant ARIZONA The biggest dust storm in living memory rolls into Phoenix on July 5, 2011, reducing visibility to zero. Desert thunderstorms kicked up the mile-high wall of dust and sand.