With dire predictions of havoc that Hurricane Sandy is expected to wreak on the region over the coming days, Westporters continued last-minute preparations for an onslaught local officials on Sunday said could be "unprecedented."

Waterfront residents are urged to evacuate by sundown Sunday.

Federal officials have warned the town to expect a 13-foot storm surge -- 3 or 4 feet higher than the inundation from Tropical Storm Irene last year. Flooding this time will be deeper and longer because of the full moon Monday night, and because Sandy is moving slowly.

At a mid-morning meeting, Fire Chief Andrew Kingsbury, the town's emergency operations manager, and First Selectman Gordon Joseloff met with all town department heads to plan for what the said could be "extensive devastation" in the coastal areas within the next 24 hours.

"This is an unprecedented storm," Joseloff said in a statement issued Sunday afternoon. "This will be a storm of long duration, high winds and record-setting flooding. Take Storm Irene from last year and double it," he said.

Kingsbury said, "The preparation window is closing rapidly. People need to use the remaining time to move their cars, secure their properties, and lay in an adequate supply of food and water -- at least three days' worth. And fair warning here, we expect the entire town to lose power, with restoration maybe taking a week or more."

All town beaches and marinas will be closed until further notice beginning at sunset Sunday.

Access to Compo Beach area to be restricted effective 8 a.m. Monday, town officials announced.

Police said there will be no public or vehicle access to the waterfront neighborhoods at Old Mill, Compo Beach and Saugatuck Shores starting at 8 a.m. Monday.

Meanwhile, the town's Department of Public Works center has been stretched trying to meet the demand for sand bag materials for residents' storm preparations over the last several days.

The town's public schools have cancelled classes both Monday and Tuesday in anticipation of the hurricane's impact, according to an announcement from Superintendent of Schools Elliott Landon.

The town's storm shelter at Long Lots School, 13 Hyde Lane, is open as of 3 p.m. Sunday. Residents planning to go to shelter should bring a change of clothes, bedding and pillows, any special medications or dietary items, and a working flashlight with extra batteries.

The shelter will accept pets as long as they are in a travel cage. People should also bring enough pet food for three days, necessary pet medications and a leash. Pets will be secured in a safe room at the shelter, but are not allowed to remain with their owners.

Up to date announcements at the town website: www.westportct.gov