NEW ORLEANS - Hurricane Isaac was downgraded Wednesday to a tropical storm but continued to pound Louisiana with heavy rains and damaging winds.
Flooding in hard-hit Plaquemines Parish, about 10 miles southeast of New Orleans, forced authorities to announce they would purposely puncture an 18-mile levee there to relieve the strain, though there was no word on when.
Isaac started losing strength earlier in the day, and was carrying maximum sustained winds of 60 mph late Wednesday evening, the National Hurricane Center reported. As of 8 p.m. ET, the storm was located about 30 miles south of Baton Rouge and 60 miles west of New Orleans. It was moving to the northwest at 6 mph. The highest official rainfall total so far from the storm was 17 inches recorded in New Orleans, though an unofficial total of 22.5 inches was reported in Arabi, La.
Isaac could become a tropical depression Thursday, when winds drop below 39 mph, the hurricane center predicts.
Despite the downgrade in strength, officials across Louisiana, Mississippi and Alabama dealt Wednesday with rescuing people who had not taken the storm warnings seriously. Thousands of customers coped with power outages. Parts of U.S. Highway 90 were flooded out in Gulfport, Miss.
MORE PHOTOS: Flood in Plaquemines Parish
One confirmed death in the region was reported so far.
In Vermilion Parish, La., a 36-year-old man fell to his death after climbing up a tree during the storm, though authorities don't know why he did this, Sheriff Mike Couvillon said.
One of the worst hit areas was Plaquemines Parish. Isaac passed directly over the region of marshland, fishing towns and marinas, peeling off roofs and flooding some areas. Video showed floodwaters reaching the rooftops of some homes.
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The northern part of the parish is ringed in by the area's hurricane protection system of fortified levees and floodwalls. But stretches of it on the east bank of the Mississippi River and further south lie outside the protection system, making it vulnerable to storm surge and flooding, Parish Councilman Kirk Lepine said.
Isaac came up the western edge of the parish, lashing at the area with powerful winds and storm surge, Lepine said.
"It came in at the worse scenario we can imagine," he said. "There's nowhere for that water to go than here."
Officials in New Orleans imposed a dusk-to-dawn curfew.
Rescue efforts were focused Wednesday in the small enclave of Braithwaite, on the east bank of the Mississippi River in Plaquemines Parish. Sheriff deputies there were conducting rescue missions of residents trapped in homes.
Flanked by marshes and water, low-lying Plaquemines Parish has been repeatedly hit by disasters - from Katrina to Gustav to the 2010 BP oil spill, Cain said. Isaac late Tuesday passed directly over the area, pummeling the parish with powerful winds and a strong storm surge.
"The geography of it makes it vulnerable," Cain said. "But talk about a resilient people. They've been through this before, and they're going to make it through this one."
Contributing: Associated Press