The Rhode Island Department of Environmental Management ordered all state beaches closed Friday because of Hurricane Earl.
The DEM also said campers in state campgrounds should consider leaving those areas until the storm has passed.
A tropical storm warning is in effect from New Haven, Conn., to Westport, Mass., and includes coastal Rhode Island and Block Island.
Earl is expected to move north-northeast for much of Friday, staying away from New Jersey and the other mid-Atlantic states, but also passing very close to Long Island, Cape Cod and Nantucket, which could get gusts up to 100 mph. The storm is expected to finally move ashore in Canada sometime Saturday afternoon.
Much of New England should expect strong, gusty winds much like a nor'easter, along with fallen trees and downed power lines, forecasters said.
"This is the strongest hurricane to threaten the northeast and New England since Hurricane Bob in 1991," said Dennis Feltgen, a meteorologist and spokesman for the National Hurricane Center. "They don't get storms this powerful very often."
Rhode Island Gov. Don Carcieri took the precautionary step Thursday by signing a "declaration of disaster emergency." It's a formal step that gives the state access to state and federal resources.
The town of South Kingstown posted a voluntary evacuation notice Thursday.
Residents were asked to leave low-lying coastal areas, including southern parts of Matunuck Beach Road from south of town beach extending to the end of Ocean Avenue, Roy Carpenter Beach, southern portions of Green Hill Beach Road and Charlestown Beach Road.
Residents are advised that if the storm changes path, it could become a mandatory evacuation order.
All state beaches in Rhode Island will be closed Friday. The DEM said beaches will reopen beginning at 10 a.m. Saturday if it is determined they are safe for visitors.
Some town beaches will also be closed Friday.
The DEM said it is requesting that campers at Charlestown Breachway and East Beach make plans to leave by 11 a.m. Friday until the storm has passed. The agency also said it is suggesting that campers at Burlingame, George Washington and Fisherman's Memorial campgrounds also plan to leave by 11 a.m. Friday.
The campgrounds will reopen when it is determined it is safe to do so, the DEM said.
Massachusetts Gov. Deval Patrick declared a state of emergency Thursday ahead of Hurricane Earl's arrival off that state's coast.
A hurricane warning has been issued for the Massachusetts coast from Westport to Hull, including Cape Cod and the Islands.
Patrick said the declaration will allow the state to respond quickly to the storm, which is expected to skirt Nantucket and Cape Cod.
Patrick urged people living in low-lying areas prone to flooding to consider leaving their homes by Friday afternoon.
Electric utility and road-clearing crews are also girding for the storm, which is expected to come closest to the state late Friday into early Saturday.
The Steamship Authority said on Thursday that ferry service from Hyannis to Nantucket is likely to be suspended before noon Friday. The agency said ferries between Woods Hole and Martha's Vineyard will continue to operate for as long as possible, but is also likely to be suspended by early or mid-afternoon on Friday.
While it's too early to say when service might be resumed on Saturday, the authority said it will attempt to run extra service to relieve any backlog of cars waiting to get off the islands.
Rhode Island Fast Ferry said the Martha's Vineyard Ferry service from Quonset is canceled Friday and Saturday. The Fast Ferry is on schedule Thursday. (Read service announcement.)
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