(CBS/AP) NEW ORLEANS - Finally reaching hurricane status, the unwieldy and wobbly Isaac bore down on this city Tuesday, offering one of the first tests for a stronger, more fortified levee system built after the catastrophic failures during Hurricane Katrina.
Seven years after that storm transformed this city, the mood was calm as the first wave of rain bands and wind gusts rolled ashore, and these battle-tested residents took the storm in stride, knowing they've been through a lot worse. Isaac looked to make landfall as early as Tuesday as a Category 1 hurricane with winds of at least 74 mph — much lower than the 135 mph winds Katrina packed in 2005.
Many residents along the Gulf Coast opted to ride it out in shelters or at home and officials, while sounding alarm about the dangers of the powerful storm, decided not to call for mass evacuations. Still, there was a threat of storm surge and the possibility of nearly two feet of rain as it slowly trudges inland.
"We don't expect a Katrina-like event, but remember there are things about a Category 1 storm that can kill you," Mayor Mitch Landrieu said, urging people to use common sense and to stay off any streets that may flood.
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Isaac became a hurricane Tuesday, a massive storm that reached more than 200 miles from its center, threatening to flood the coasts of four states with storm surge and heavy rains on its way to New Orleans, with surface wind speeds of 75 mph and flight-level winds even stronger, at 110 mph.
Meteorologist Jeff Berardelli of CBS Miami station WFOR-TV reports one factor that delayed Isaac from developing into a hurricane was that dry air to the north of the storm inhibited those stronger flight-level winds from dropping down to the surface.
WFOR Miami's interactive storm tracker
Weather models indicated that Isaac will slow down when it makes landfall, possibly dropping between 15 inches and 20 inches of rain on a very large area that may include New Orleans, Berardelli reports. Isaac could also cause between 6 feet and 12 feet of storm surge east of the storm's center.
Berardelli notes that the outer bands of rain rotating into Isaac's center pose a tornado threat. Because the tornadoes move extremely fast and are wrapped in rain, they can't be seen coming.
Isaac was centered about 75 miles southeast of the mouth of the Mississippi River at midday and was moving northwest at 10 mph.
In New Orleans, Landrieu insisted the city was ready, CBS News correspondent Byron Pitts reports. When asked about the comfortable and confident stance people have about the storm - and if that's a good place to be - Landrieu said, "I think what they're comfortable and confident in is that, given the level of this storm, that the levees can hold and we're not gonna have a Katrina event."
In Cocodrie, La., the biggest concern was the expected storm surge, CBS News correspondent Manuel Bojorquez reports. Two major flood gates meant to protect this coastal community are still under construction. One of them, the Houma Navigation Canal, won't be complete until next hurricane season. Everyone in the area is under a mandatory evacuation notice.