Hurricane Isaac hit New Orleans, Louisiana early Wednesday.<br/> <br />It was exactly seven years ago to the day that Hurricane Katrina devastated the Crescent City.<br/> <br />Although Isaac is a Category 1 and Katrina was a Category 3 when it made landfall, officials say this will be the first test for the city's multi-billion dollar flood defense system.<br/> <br />About 1,000 U.S. National Guard troops have been deployed throughout the mostly deserted city.<br/> <br />Oil production in the Gulf of Mexico nearly ground to a halt and ports and coastal refineries curtailed operations.<br/> <br />The National Hurricane Center warned late on Tuesday that Isaac and its 80 mph (130kph) winds were producing dangerous storm surges, and that flooding was to be expected.
