et ] water that overtopped levees was trapped in plaquemines parish with nowhere to drain .
parish president billy nungesser said .
the category 1 hurricane has pushed water over a rural levee to flood some homes , knocked out power and immersed beach - front roads in louisiana and mississippi as it makes a drenching slog inland from the gulf of mexico .
it will be saturday , at the earliest , before crews can cut the levee some local residents with boats have begun rescue efforts for plaquemines parish residents stranded by hurricane isaac along its east bank , outside the federal levee system .
a tornado warning has been issued in southern mississippi as hurricane isaac moves through southeast louisiana , bringing wind , rain and flooding .
most of the outages wednesday are in areas around new orleans as isaac lashes the area with 80 mph winds .
the warning comes as category 1 isaac 's dangerous storm surges and flooding and power outages after making landfall tuesday evening .
new orleans mayor imposes dusk - to - dawn curfew more than 817,000 without power across 5 states isaac 's maximum sustained winds slip to 60 mph emergency crews rescue people stranded by floods refresh this page for the latest updates or read the full cnn story here .
wind gusts of more than 60 mph and sheets of rain pelted new orleans , where people braced themselves for the storm behind levees that were strengthened after the much stronger hurricane katrina hit seven years ago to the day .