Sandy will make its way up the coast before making landfall, which is now expected to be around southern New Jersey or Delaware, late Monday or early Tuesday. A 4- to 10-foot coastal surge is expected to affect areas from Washington, D.C., to New York, as bad or worse than Hurricane Irene, which caused $14 billion worth of damage in 2011.
"Certainly having lived through it, lost everything in my basement -- I had 10 feet of water in my house -- this is a concern," Staten Island resident Iris Baum said.
Communities all along the East Coast are building sand walls and stocking up on supplies to ready themselves for the monster storm. It could bring almost a foot of rain, high winds and up to two feet of snow.
In New York, Gov. Andrew Cuomo declared a state of emergency, and New York City Mayor Michael Bloomberg warned residents to brace themselves.
"There's the possibility of parts of our city flooding, or high winds that could force certain bridges to be closed," Bloomberg said.
Bloomberg made the unprecedented call to evacuate low-lying parts of the city and shut down the subway system before Irene hit last year. It is not clear whether he'll implement another shutdown for Sandy.
Even residents of central Pennsylvania and Connecticut are worried. As farmers hastened to move equipment to higher ground, politicians canceled public events and residents were cautioned to prepare for days without electricity.
"Be forewarned," Connecticut Gov. Dannel P. Malloy. "Assume that you will be in the midst of flooding conditions, the likes of which you may not have seen at any of the major storms that have occurred over the last 30 years."
The Associated Press contributed to this report.