Emily Schneider leans against a pole to support herself against strong winds while visiting the banks of Lake Pontchartrain in New Orleans, Louisiana, on Tuesday, August 28, where Hurricane Isaac has made landfall. 
Water rises from a bayou, flooding properties ahead of the arrival of Hurricane Isaac in Bay St. Louis, Mississippi. 
Bridgette Mooney, her husband Kevin, and their 15-month-old daughter Skyler watch from their home as Hurricane Isaac lashes their property with rain in Kiln, Mississippi. 
Employees of the Orleans Levee District remove signs from Lake Shore Drive near the shore of Lake Pontchartrain. 
Evan Stoudt faces strong winds from the banks of Lake Pontchartrain. 
A man walks on Canal Street in New Orleans. 
Joshua Keegan and Ruffin Henry swim at Lake Pontchartrain. 
High surf splashes along Highway 193 north of the Dauphin Island Bridge in Alabama. 
Waves from Hurricane Isaac smash against a warning sign at a flooded beach in Biloxi, Mississippi. 
A group of men sit on a bench at the edge of Lake Pontchartrain as Hurricane Isaac approaches. 
Matthew Pettus holds a sheet open in the wind on the levee near Lake Pontchartrain. 
People make their way across Canal Street in New Orleans. 
Joshua Keegan and his dog Scout swim in the rising water of Lake Pontchartrain. 
A Mississippi Department of Transportation sign in Hattiesburg warns southbound motorists on U.S. 49 of rough weather conditions on Tuesday, August 28. Hurricane Isaac is expected to drop heavy rain on the Mississippi Coast over the next couple of days. 
A woman and her dog watch the waves produced by Hurricane Isaac on the shore of Lake Pontchatrain in New Orleans on Tuesday. Hurricane Isaac is expected to make landfall later tonight along the Louisiana coast. 
Louisiana Gov. Bobby Jindal and New Orleans Mayor Mitch Landrieu receive an update on the status of the pumping station at the 17th Street Canal in Metairie, Louisiana. 
A couple takes photos in Bay St. Louis, Mississippi. Many residents of the area decided to stay in their homes instead of evacuating. 
A man skateboards past a bar with boarded windows in the French Quarter in New Orleans. 
Diana Whipple of New Orleans watches waves crash on the shore of Lake Pontchartrain as Hurricane Isaac approaches Tuesday. Isaac became a Category 1 hurricane Tuesday when its maximum sustained winds reached 75 mph, the National Hurricane Center says. 
Workers try to close off state Highway 23 South in Oakville, Louisiana, on Tueday as Issac heads toward the coast. 
Gallery Nine Forty in New Orleans' French Quarter notifies customers it's "on Hurrication." 
Workers board up a business on Bourbon Street in the French Quarter as Isaac approaches Tuesday. 
Hydraulic pumps are prepared at the 17th Street Canal floodwall Tuesday in New Orleans. 
A woman enjoys the a heavy rain in the Tampa, Florida, area, on Monday. Hurricane Isaac is expected to make landfall near New Orleans. 
Mounted law enforcement officials wait out a brief rainstorm during the National Republican Convention. Commercial bus cancellations caused by Isaac prevented many of the expected demonstrators from being present. 
A sign in the French Quarter makes fun of Hurricane Isaac. 
Workers place plywood on the windows of the Royal Sonesta Hotel on Bourbon Street. 
Aimo Ny rests on her cot in the hurricane shelter at the Belle Chasse Auditorium on Monday in Belle Chasse, Louisiana. 
iReporter Liz Yavinsky snapped this picture of a boy floating down a flooded street in West Palm Beach, Florida, on Monday. 
The manager of a shoe store in Harvey, Louisiana, places plywood over the windows in preparation of Hurricane Isaac. 
A crew from Jefferson Parish Drainage Department places large sandbags near a canal and pond in Jean Lafitte, Louisiana, on Monday in preparation for Isaac. 
A St. Petersburg, Florida, resident walks along the sea wall at Spa Beach, where larger than average waves were being kicked up by Tropical Storm Isaac on Monday. 
Oliver Marti sweeps water from heavy rains generated by Tropical Storm Isaac off the roof of his flower shop on Monday in Tampa, Florida. 
Waves batter the coast in Havana, Cuba, on Sunday after Tropical Storm Isaac passed the island. 
Larry Hoffmeister, left, and Charles Carter place storm shutters on Carter's vacation home on Dauphin Island, Alabama, as they prepare for Isaac on Sunday. 
Justin and Kayla Franklin of Tennessee walk in wind and rain in downtown Key West as Tropical Storm Isaac moves over the island. 
Biloxi, Mississippi, resident Stephanie Dale fills out paperwork Sunday to have her dog microchipped at the Humane Society of South Mississippi, which opened its doors to provide an emergency microchip and tag clinic. 
Ocean Springs, Mississippi, resident Charles Bartlett fills several gas containers in preparation for Isaac. 
Andrew Marino, left, and Colby Collier pull a wagon filled with sandbags back to their homes as Florida residents prepared for Tropical Storm Isaac in St. Pete Beach, Florida, on Sunday. 
Palm trees blow in the wind in front of the Tampa Bay Times Forum, where the start of the Republican National Convention was pushed to Tuesday. 
Earl, right, and Terri Harris place sandbags around their home to prepare for possible flooding. 
A couple watch as waves and strong winds from Tropical Storm Isaac, which crossed Cuba on Sunday, batter the shore in Gibara, Cuba, on Saturday. 
Strong winds bend palm trees in Cuba's northern province of Sancti Spiritus on Saturday. Isaac is expected to strengthen and become a Category 1 hurricane by early Monday as it draws nearer to Florida. 
A man captures the effects of Tropical Storm Isaac in Gibara. 
People watch from the shore as waves pound the coast in Gibara. 
Officials reported some storm surge and flooding in eastern Cuba. 
Tampa, Florida, area residents make preparations for the arrival of Tropical Storm Isaac by filling sandbags at a Hillsborough County Public Works Service Center on Saturday. 
A woman sits atop sandbags filled by Tampa area residents in preparation for the storm. 
Two men install storm shutters on Duval Street on Saturday. 
Vehicles cross a bridge leaving the Lower Keys on Saturday as the storm strengthens and moves closer. 
- "People who went through Katrina are pretty nervous," says a New Orleans resident
- Isaac is churning slowly at about 7 mph along the coast of Louisiana, forecasters say
- Roughly 310,000 people are without power in Louisiana, officials say
- About 1,000 National Guard soldiers and 2,700 police are in New Orleans, the mayor says
Have you been affected by Isaac? Share your photos here.
(CNN) -- The fury of Isaac slammed into Louisiana with strong winds and pounding rain, generating the first real test early Wednesday of flood control systems and emergency services in New Orleans on the seventh anniversary of Hurricane Katrina.
With forecasters warning Isaac was generating dangerous storm surges and flooding from heavy rain, all eyes were on the New Orleans levy system that was rebuilt and reinforced after it failed when Katrina struck in 2005.
Nearly 1,800 people died in Katrina, the majority when levies failed and flooded New Orleans.
"People who went through Katrina are pretty nervous about storms, and large numbers of people have left," Lynn Magnuson, 58, said in a CNN iReport.
Hurricane Isaac causing heavy rainfall 
Hurricane Isaac's wall of water 
Hurricane Isaac landfall in Louisiana 
Will the levees hold in New Orleans? 
See Isaac brewing from space 
Fugate: FEMA in good shape for Isaac Magnuson said the Lower 9th Ward, which was hard hit by Katrina, "is pretty empty right now."
Issac -- with sustained winds of 80 mph -- was churning slowly about 7 mph along the coast of southeast Louisiana, about 70 miles south of New Orleans, the National Hurricane Center said.
"We're in a hunker down phase now, because this storm could be over us for a while with a lot of wind and rain," New Orleans Mayor Mitch Landrieu said.
"Hunker down means hunker down and prepare to ride it out."
Even with more dangerous conditions likely yet to come, the storm already has caused significant surges and flooding in a number of locales, and not just those directly in Isaac's path. Storm surges of 9.9 feet have been reported in Shell Beach, Louisiana, and 6.2 feet in Waveland, Mississippi, according to the hurricane center.
These surges likely will get worse, with forecasters predicting water levels to rise between 6 to 12 feet on the coast in Mississippi and southeastern Louisiana alone.
The worst of the storm was expected to hit New Orleans in the early morning hours Wednesday, though the first to feel its fury was Plaquemines Parish where Isaac first made landfall Tuesday night before moving back out over the water toward the mouth of the Mississippi River.
"We took the brunt of Katrina, and we are doing it again for this one," Parish President Billy Nungesser told CNN.
Strong winds ripped through the parish, knocking down utility and power poles.
At Nungesser's brick house, he said the wind was so strong that "it's pushing rain through the cracks" into the house.
"The light sockets are spraying you with water like you a hose hooked up there," he said.
Isaac, which started as a tropical storm last week in the Atlantic Ocean, has killed nearly two dozen people in Haiti and the Dominican Republic before starting its journey across the Gulf of Mexico.
On Tuesday, Isaac was classified as a Category 1 hurricane. It is significantly weaker than Category 3 Katrina, though forecasters warn it is capable of causing significant flooding.
"There is no evidence of any (water) overtopping (canals)," Landrieu said. "We have full confidence the levees will hold."
Even so, he and other officials were taking no chances.
The mayor tweeted that about 1,000 National Guard troops and more than 2,900 law enforcement officers are in the city ready to address issues related to the storm.
Power had been knocked out to more than 310,000 customers in Louisiana by the storm, while localized street flooding and downed electrical wires were reported across New Orleans, according to the city.
Isaac earlier prompted three airports to close -- in New Orleans; Gulfport-Biloxi, Mississippi; and Mobile, Alabama -- and cancellations of around 1,500 flights, according to airline and airport officials.
Major ports along the Gulf Coast and the Mississippi River from Baton Rouge to its mouth have been closed, according to the Coast Guard.
Amtrak suspended its train service to and from New Orleans on Wednesday because of Isaac.
Business also came to a standstill because of Isaac.
Fifty-two Walmart and Sam's Club stores in Louisiana and nine in Mississippi were shuttered Tuesday, their parent company said.
In Mississippi, more than 1,800 people were staying in 33 shelters located in 16 counties, according to the state's emergency management agency.
Shrimpers in Bayou Le Batre, Alabama, were among those who heeded official warnings and hunkered down.
The Nuclear Regulatory Commission said it was sending additional inspectors to two Louisiana nuclear plants in the storm's path, as power company Entergy planned a "controlled shutdown" of one of them starting Tuesday afternoon.
CNN's Ed Lavandera, Anika Chin, Mike Ahlers, Aaron Cooper and Ed Payne contributed to this report.
