NEW ORLEANS (AP) -- Hurricane Isaac has made landfall in southeast Louisiana with winds near 80 mph.

The U.S. National Hurricane Center says the storm's center reached land at 7:45 p.m. in Plaquemines Parish, about 90 miles southeast of New Orleans.

The storm's arrival Tuesday evening comes on the eve of the seven-year anniversary of Hurricane Katrina, which devastated the region.

While not as powerful as Katrina, Isaac threatens to flood the coasts of four states with storm surge and heavy rains on its way to New Orleans, where residents have been hunkering down behind levees fortified after Katrina struck.

Isaac also promises to test a New Orleans levee system bolstered after the catastrophic failures during Katrina.