Officials in southern New Jersey are preparing for a doomsday scenario as monster hurricane Irene is expected to smash into the Jersey shore on Sunday morning, with winds of up to 90 miles per hour.

Cape May County, at the southernmost tip of New Jersey, has ordered a mandatory evacuation -- meaning up to three-quarters of a million people will be made to leave.

The National Weather Service said there is a 90 percent chance that Cape May will suffer a direct strike from Irene. Forecasters are predicting between 5 to 10 inches of rain pounding the area over the weekend.

Cape May County stated on its website: “Hurricane warning is in effect. Mandatory evacuation continues in Cape May County. At this time all roads and bridges are open. Tolls have been lifted on all county bridges and on the Garden State Parkway.”

Frank McCall, Cape May County's emergency management coordinator, told local media that other shore counties (Atlantic, Ocean and Monmouth) further up the coast will likely issue similar evacuation orders.

McCall also indicated that Cape May is the sixth most difficult area in the U.S. to evacuate because of its peculiar geographical characteristics.

During the evacuation, the New Jersey State Police and the Department of Transportation will coordinate traffic flow out of Cape May County with the assistance of county and municipal agencies.

Avalon, a wealthy barrier island in Cape May popular with tourists, has already warned visitors to stay away for the duration of the hurricane. In order to avoid the potential gridlock of a mass evacuation, borough officials are asking renters and others to depart by Friday.

Meanwhile, local electric utility Atlantic City Electric, warned of power outages across the region – and that it may take a few days for full service to be restored.

South Jersey has not faced a mandatory evacuation since 1985 when Hurricane Gloria struck.

New Jersey Governor Chris Christie has already declared a state of emergency for the state, and gave particular warning to the most vulnerable coastal communities.

The current tracking of the storm is not positive for our state, he said.

So if you're being directed by emergency management personnel at the local or state level to go someplace else, do not try to ride it out. I will not order evacuations unless it's absolutely necessary but if I do order it expect it to be complied with. I understand sometimes folks think we overreact in a situation like this. We are not overreacting.