The northeastern United States, still recovering from Hurricane Sandy, Wednesday braced for rain, winds and snow from a powerful nor\'easter churning offshore. Gusting winds threatened to cause more damage to areas hit last week, and could also drive ocean water into communities now lacking protective beachfront sand dunes, Accuweather.com said Wednesday. Snow, and snow mixed with rain, brought delays to airports in Philadelphia and New York, it said. The approaching storm triggered more than 880 flight cancellations at New York City\'s three major airports. Newark had 362 cancellations and LaGuardia and Kennedy had 265 and 183 cancellations, respectively, data from FlightStats said. Airlines, just returning to normal after Hurricane Sandy caused more than 20,000 flight cancellations, are reverting to policies that include the waiving of cancellation and flight change fees, ABC News reported. New Jersey Governor Chris Christie said Wednesday emergency crews are at work building up badly eroded beach dunes, USA Today reported. \"We\'re doing what we need to do to prepare for this, just like we did for Hurricane Sandy,\" he said. \"We no longer have a dune system,\" Councilwoman D\'Arcy Rohan Green added. \"There are just piles of sand back on the beach.\" The National Weather Service predicted the storm will last into Thursday, bringing up to three inches of wet snow to the Philadelphia area and six to 12 inches of snow to southeast New York State and New England. New York City \"is taking significant precautions in advance of the storm, including halting all construction, closing all city parks and encouraging drivers to stay off the road after 5 p.m.,\" Mayor Michael Bloomberg said. He warned the upcoming storm will likely compound issues created by last week\'s by the superstorm, CNN said.