Coastal flooding alerts were issued from New Jersey to Massachusetts with winter weather advisories, winter storm warnings and high wind warnings in effect from the Northeast to the Mid-Atlantic, the National Weather Service said.
Winter Storm Riley dropped more than a foot (30.5 centimeters) of snow in the western and northern parts of New York state, as heavy rain lashed coastal areas. The storm is expected to taper off overnight or by early Saturday.
Police in James City County, southern Virginia, confirmed a 44-year-old man was killed when a tree fell on the truck he was traveling in -- while in Chesterfield County, south of Richmond, authorities said a six-year-old boy was killed when a fallen tree struck him as he slept in his home.
Outside Baltimore, an elderly woman, 77, was also killed when she was hit by a large tree branch in Kingsville, Baltimore County Police & Fire Department said in a statement.
Meanwhile, local media said fallen trees also killed an 11-year-old boy in Putnam Valley, New York, and a man in his 70s in Newport, Rhode Island.
More than 3,000 domestic and international flights were cancelled on Friday and more than 2,400 others were delayed, according to the website FlightAware.
More than half the flights scheduled to arrive and depart from New York's LaGuardia Airport were cancelled, with sweeping disruptions at Boston Logan International and New York's two other area airports, Newark and John F. Kennedy International.
Amtrak, the US public railway service, announced that "for safety" all services along the northeast corridor were temporarily suspended.
Trains already en route between the US capital, New York, and Boston would continue to their destinations and hold, it said.
New York, the most populous US city and home to 8.5 million people, was expected to avoid heavy snow but was forecast to receive two to three inches (six centimeters) of rain and wet snow, with gusts of up to 60 miles per hour (96 kilometers per hour).
New York state governor Andrew Cuomo warned that Long Island and New York City would see winds of 40 mph, with gusts as high as 70 mph possible in eastern Long Island. Wind at that speed has the potential to uproot trees and cause power outages.
In the federal capital Washington and surrounding suburbs, public schools were closed because of the storm, which some dubbed online as "Windmaggedon".
A plane coming in to land at the Ronald Reagan airport was forced to abort its first attempt amid intense wind before touching down 10 minutes later, according to ABC news, which broadcast footage of the incident.
A pilot landing at the capital's Dulles International Airport meanwhile reported to authorities that the descent of his United Airlines flight from Charlottesville, Virginia, was so turbulent that "pretty much everyone on the plane threw up."
Dulles also briefly evacuated its control tower due to high winds.
In Massachusetts, authorities reported more than 100,000 power outages by mid-afternoon, warning that additional power cuts were likely and ordered some coastal communities to evacuate, warning that they expected homes to sustain significant damage.
State police announced the closure of roads and businesses in coastal areas as the National Weather Service warned that shoreline neighborhoods would stay inundated and cutoff, with water unable to drain until the storm passes.
Weather forecasters urged people to avoid driving through flood waters or heading to the coast to watch the flooding, flagging reports of stranded motorists.