lying city's levees and flood its historic French Quarter when it makes a second, and more powerful, assault on U.S. shores. It killed seven people in Florida on Thursday. "Ladies and gentlemen, I wish I had better news for you but we are facing a storm that most of us have feared," Nagin told a news conference after reading out a mandatory evacuation order. "This is a threat that we've never faced before." Katrina was a Category 5 hurricane on the five-step Saffir-Simpson scale, with catastrophic winds of 175 mph (284 kph), just before 2 p.m. EDT (1800 GMT) on Sunday, said the U.S. National Hurricane Center in Miami. Its central pressure -- a measure of a storm's intensity -- fell to 906 millibars, making Katrina the second strongest storm on record after the Labor Day hurricane of 1935 that hit the Florida Keys. That storm recorded a minimum central pressure of 892 millibars on landfall. --More 2232 Local Time 1932 GMT
