Photo Gallery: Hurrricane Isaac 40/70

Workers put up shutters at a local cafe in Key West, Fla., Sunday, Aug. 26, 2012, as the prepare for Tropical Storm Isaac. Isaac gained fresh muscle Sunday as it bore down on the Florida Keys, with forecasters warning it could grow into a dangerous Category 2 hurricane as it nears the northern Gulf Coast. (AP Photo/Alan Diaz) ORG XMIT: FLAD104