The US Eastern Seaboard is getting back on its feet after severe blizzards forced the cancellation of thousands of flights and left many homes without power.
Flights have now resumed into and out of New York, Boston and Philadelphia. But many passengers were expected to be stranded until the end of the week after some 7,000 flights were cancelled over the post-Christmas travel period.
With many flights already expected to be nearly full between the peak Christmas and New Year travel period, airlines are struggling to accommodate all the stranded passengers in the New York area.
American Airlines spokesman Ed Martelle said: “Any airline scheduler will tell you it’s like playing with a jigsaw puzzle where all the pieces keep changing shape.”
Three airports serving New York - JFK, La Guardia and Newark Liberty International Airport - and also Boston’s Logan and Philadelphia International reopened on Monday evening.
They had been closed since early morning, forcing thousands of passengers to camp out on floors in terminals. Analysts say the storm and its aftermath could cost the airlines up to $100m.
Tens of thousands of homes were left without power in Massachusetts, New York City and Westchester County, Long Island and New Jersey.
Five deaths were reported in road accidents in the storm, four in the Carolinas and one in Maine, according to the New York Times.
National rail operator Amtrak - which earlier shut its New York-Boston route - announced a limited resumption of services.
The US National Weather Service says the monster snow storm is the result of a low pressure system which originated off North Carolina.
Six US states - Massachusetts, Maine, Maryland, New Jersey, North Carolina and Virginia - earlier all declared emergencies.
The New York area received up to 51cm (20in) of snow over the last two days.
A subway train in New York City was trapped for seven hours before passengers were rescued.
The southern states of Georgia and South Carolina had their first white Christmas in more than a century.