Looming power outages are “a huge concern of ours,” Maryland Gov. Martin O’Malley (D) said Saturday afternoon as Hurricane Irene bore down on the state.

“We do anticipate widespread outages,” O’Malley said during a press briefing that started about 3:25 p.m. As of that time, the state had experienced 12,458 outages, a number that is expected to grow substantially, he indicated.

The governor said he has been told to expect the center of the storm to arrive in Maryland “right around midnight,” with the eye nearly directly over Ocean City. O’Malley said he expects storm surges of three to five feet.

Earlier this afternoon, President Obama declared a federal state of emergency for Maryland, making it the eighth state along with New York, Massachusetts, Connecticut, New Jersey, Virginia, New Hampshire and North Carolina.

O’Malley, who was joined at the State Emergency Operations Center in Reisterstown by Sen. Benjamin L. Cardin (D-Md.), praised the work of federal officials in helping prepare for the storm, saying they had provided “some outstanding cooperation and leadership.”

O’Malley said he had participated earlier in the afternoon in a conference call with President Obama, whom he thanked for signing an emergency declaration for Maryland on Saturday.

“This is a big event,” O’Malley said. “It spans many states.”

O’Malley said evacuations of Ocean City and other localities had gone well. As of the time of the briefing, 4,038 people were in shelters in Maryland, he said.

Transportation Secretary Beverley K. Swaim-Staley said that wind restrictions are now in place on the Bay Bridge that prohibit house trailers and various other vehicles from crossing. If sustained wind speeds pick up Saturday night, as expected, the bridge will be closed to all traffic.

O’Malley said he plans to hold another briefing at 5 p.m.