STATEN ISLAND, N.Y. -- With Hurricane Sandy threatening a storm surge as high as six to 11 feet, Mayor Michael Bloomberg said Sunday he will sign an order mandating the evacuation of Flood Zone A -- an area that includes tens of thousands of Staten Island residents in coastal neighborhoods.

Bloomberg also ordered the city's public school system closed on Monday, and possibly longer depending on the storm.

"This is a serious and dangerous storm," Bloomberg said during an 11:30 a.m. press conference.

He urged residents in the evacuation zone to abide by the mandate and not to attempt to remain in their homes.

Flood Zone A includes tens of thousands of Staten Island residents along all four shores, in communities like South Beach, Midland Beach, Ocean Breeze, Tottenville, Prince's Bay and St. George.

If you leave in these areas, you are required to leave as soon as possible, but no later than Sunday night.

Evacuated Staten Islanders can go to one of five evacuation centers on the borough: Curtis High School in St. George, Markham Intermediate School in Graniteville, Petrides Complex in Sunnyside, Susan Wagner High School in Sea View, and Tottenville High School.

Bloomberg said a decision would be made Monday afternoon or evening regarding whether the public school system would be open on Tuesday.

Earlier Sunday, Gov. Andrew Cuomo announced

. The system would remain closed until the storm threat passes. But it's possible the shutdown could last until Wednesday.