Hurricane Isaac makes landfall as category 1 in south-eastern Louisiana

Hurricane Isaac made landfall as a category 1 storm with top wind speeds of 80mph Tuesday in extreme south-eastern Louisiana, where authorities warned that the slow-moving storm could hit inland areas as well as coastlines hard.

The National Hurricane Center reported "strong winds and a dangerous storm surge" along the Gulf coast after the storm came ashore at 7:45pm ET. A second landfall was expected overnight, the Guardian reports.

As wind and rain intensified in New Orleans as the hurricane made landfall at the extreme southern part of the Plaquemines Parish region, mayor Mitch Landrieu held a press conference at 8pm ET. "The message of this press conference is to let you know that your city is secure," he said.

More road closures this afternoon have made leaving the city increasingly difficult. The mayor warned residents to stay indoors because of the risk of flying debris and flooding. "We're in the hunker-down phase," he said.

As of 9pm ET, Entergy Corp was reporting 130,000 were without power in Louisiana. Most parts of New Orleans and the surrounding areas were expected to suffer power cuts overnight and into Wednesday afternoon.

The National Hurricane Center had warned in its 5pm ET update that Isaac was getting better organised as it neared southeastern Louisiana. Isaac had picked up force, with maximum sustained winds measured at 80mph.

President Barack Obama signed emergency declarations for Louisiana and parts of Mississippi and warned against overconfidence. "We're dealing with a big storm and there could be significant flooding and other damage across a large area. Now is not the time to tempt fate. Now is not the time to dismiss warnings," he said.

Speaking in Mississippi, Craig Fugate, head of the Federal Emergency Management Agency, warned that the storm was slow moving and that heavy rains could cause inland flooding. "This is not just a storm for the coastal counties," Fugate said.

The Louisiana governor, Bobby Jindal, said the storm's slow speed of 10mph meant some areas of New Orleans would experience six to 10 hours of hurricane-force winds and that storm surges could top 10ft. He said 41 parishes had declared emergencies, and seven were at least partially evacuated.

Seven years almost to the day after Katrina hit, New Orleans was hoping that that $14.5bn worth of civil works - a 133-mile chain of levees, flood walls, gates and pumps - would avert another catastrophe.

Mitch Landrieu, the mayor, did not order an evacuation of the city, but those living outside the levee system were strongly encouraged to leave. "We don't expect a Katrina-like event, but remember there are things about a category 1 storm that can kill you," Landrieu said.