Isaac has top sustained winds of 70 mph, just below the hurricane threshold of 74 mph. The storm was about 50 miles west-southwest of New Orleans at 2:00 pm Wednesday, where it was bringing drenching rains and fierce winds.

City officials are imposing a dusk-to-dawn curfew beginning Wednesday because of the downed power lines and generally unsafe conditions.

Police cars have been patrolling the nearly empty streets since Isaac began bringing fierce winds and heavy rains to the city Tuesday night. The curfew was set to start Wednesday night and would last until further notice.

Rescuers in boats and trucks plucked a handful of people who became stranded by floodwaters in thinly populated areas of southeast Louisiana. Authorities feared many more could need help after slashing rain and fierce winds knocked out power to more than 600,000 households and businesses.

Gov. Bobby Jindal says coastal officials may intentionally break a levee on the east bank of flooded Plaquemines Parish to relieve pressure on the structure.

At a news conference in Baton Rouge, Jindal said there's no estimate on when that might occur.

In spite of Isaac beging downgraded, forecasters are warning there are still life-threatening hazards from the storm surge and inland flooding.

Here is video from Wednesday afternoon: