There were no reports of injuries but dozens of residents of Plaquemines Parish, La., were stranded atop a levee, while there were multiple reports of people trapped in attics by rising waters. Thus far, fewer people were evacuated than during Hurricane Katrina, which hit New Orleans seven years ago today.
But the Category 1 slow-moving storm is expected to stay over the region all day with its drenching rains and high winds, while heading northwest at 6 miles per hour in a northwest trajectory, which is expected to continue through tonight.
As of 11 a.m. the storm's center was about 45 miles southwest of New Orleans, according to the National Hurricane Center.
At 9 a.m., 30 to 40 vehicles were stranded atop the levee in Plaquemines waiting for a ferry, with water all around, according to a contactor who works for the parish. That ferry is the only way off that flooded spit of land. A source told ABC News that nearly the entirety of the area has been flooded, and winds still howling at 35-40 mph, preventing a ferry from approaching.
It is estimated that it will be six to eight hours before it's safe for the ferry to motor out to the stranded people, who were without power but do have cell phone service.
Thousands who live in the area are still stuck in their homes or attics, and rescuers are out in boats helping those who need it most.
"I've got a four-by-four hole in my roof, several pieces in the front yard, the back wall of my house moved a couple of feet, and with each gust of wind, it's like you're breathing in and out," William Harold "Billy" Nungesser, president of Plaquemines Parish, told "Good Morning America."
Nungesser confirmed that a levee in Plaquemines Parish was overtopped with water, causing flooding. So far there were no reports that the $14 billion of levees and pumps put up around New Orleans after Katrina have been breached, but officials have not yet fully assessed the situation.
"The water came up so quickly and overtopped the levees from Breakaway to White Ditch on the east back of the north end of the parish. It's an area that we called for a mandatory evacuation," he said.
WATCH: Billy Nungesser: 'This Storm Has Been Relentless'
At daylight, parish officials were out examining the damage, according to James Madere, a parish geographic information system analyst. The Plaquemines Parish Public Information Office tells ABC News that rescue operations will not start until it is safe, possibly as late as 1 p.m. ET.
In New Orleans, power lines were down, snaking and sparking across city streets after transformers exploded across the city Tuesday night.
The city saw handfuls of arrests early as looters took advantage of the chaos, sheriffs and police and National Guard were all out in force.
The hurricane promised to lend even more solemnity to commemoration ceremonies Wednesday for Katrina's 1,800 dead in Louisiana and Mississippi, including the tolling of the bells at St. Louis Cathedral overlooking New Orleans' Jackson Square. This storm is far less powerful at Category 1 than Katrina, which caused at least $81 billion in damage and was rated as the most powerful Category 5 storm.
WATCH: Hurricane Isaac Hits New Orleans: A Night in the Ninth Ward
As of 11 a.m., Isaac was still packing winds of 75 mph, decreased from 80 mph at 9 a.m. Isaac is moving at near 6 mph and has already dropped more than six inches of rain on New Orleans during the seventh anniversary of Hurricane Katrina. Hurricane force winds extend 60 miles from the center of the storm.
The hurricane had moved back into the Gulf of Mexico after making its initial landfall Tuesday evening. Isaac's center remained over water where it was almost stationary before making landfall again this morning.
At 11 a.m., the tropical storm warning was discontinued east of the Alabama-Florida border.
The 200-mile wide hurricane is expected to gradually weaken and move inland in a northwestward motion, dumping seven to 14 inches of rain across Louisiana, with some places receiving up to 20 inches, according to forecasters.
The greatest concern is an expected storm surge of between six and 12 feet off the Louisiana and Mississippi coasts, four to eight feet along the Alabama coast and three to six feet on the Florida Panhandle, according to the Hurricane Center located in Miami. A storm surge of 8 feet was reported at Shell Beach, La. and in Waveland, Miss., according to the Hurricane Center late Tuesday.
In Mississippi, highway U.S. 90 was closed in sections by storm surge flooding. At one spot in Biloxi, a foot of water covered the in-town highway for a couple of blocks and it looked like more was coming in. High tide around 9:30 a.m. was likely to bring up more water.
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Tornado warnings swarmed the state throughout the morning as 55 mile per hour gusts hit the region.
The highest wind gust was recorded at 113 miles an hour overnight in Belle Chasse, Plaquemines Parish, La.
Thursday night into Saturday, Isaac will move into the Mississippi Valley and eventually into Illinois and Indiana with possibly six inches of rain for the drought-stricken Midwest.
Isolated tornadoes are possible along the central Gulf Coast region and part of the lower Mississippi River Valley through Wednesday, according to the National Oceanic and Atmospheric Administration.
Entergy New Orleans has listed more than 400,000 homes and businesses without power as of 5:30 a.m., according to their website. The Red Cross reported 18,000 people in 70 shelters across five states Wednesday morning.
While traffic was nearly invisible Tuesday night, a few French Quarter bars remained open and filled with locals in New Orleans. At Lafitte's Blacksmith Shop -- the 150-year old dive at the end of Bourbon Street -- Chris LaRue recommended the four staples of hurricane preparedness, "Water, canned food, candles and booze."
"We're going to have some water to clean up," said LaRue. "But this kind of wind is nothing."
In advance of the storm, Louisiana set up shelters and stockpiled more than a million packaged meals, 1.4 million bottles of water and 17,000 tarps.
Since the levees failed in Katrina seven years ago, more than $14 billion has been spent on the 133 miles of floodwalls, spillways, gates and pumps surrounding New Orleans.
Entergy New Orleans has listed more than 400,000 homes and businesses without power as of 5:30 a.m., according to their website. The Red Cross reported 18,000 people in 70 shelters across five states Wednesday morning.
While traffic was nearly invisible Tuesday night, a few French Quarter bars remained open and filled with locals in New Orleans. At Lafitte's Blacksmith Shop -- the 150-year old dive at the end of Bourbon Street -- Chris LaRue recommended the four staples of hurricane preparedness, "Water, canned food, candles and booze."
"We're going to have some water to clean up," said LaRue. "But this kind of wind is nothing."
In advance of the storm, Louisiana set up shelters and stockpiled more than a million packaged meals, 1.4 million bottles of water and 17,000 tarps.
Since the levees failed in Katrina seven years ago, more than $14 billion has been spent on the 133 miles of floodwalls, spillways, gates and pumps surrounding New Orleans.
ABC News' Max Golembo and The Associated Press contributed to this report.
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