Hundreds of flights have been canceled because of the storm.

More than 770 flights within, into or out of the United States were canceled on Monday, according to FlightAware.com, with many of the scrubbed flights involving the New York and Boston airports.

Anthony and Amy Burt, newlyweds from Devon, England, who have been celebrating their honeymoon in Maine the past two weeks, were concerned that their flight back home from Boston on Tuesday might not take off as planned.

“The snow is hitting pretty hard up here i n Portland,” Mr. Burt said.

Portland had received nearly two inches of snow by Monday afternoon, but another six to 10 inches was expected to fall by Tuesday morning. Some places in southern parts of the state, in particular York County, had already seen more than nine inches of snow.

“We have prepared ourselves for the drive to Boston tomorrow by putting snacks in the car, water and tea,” Mr. Burt said, adding that he had made sure the car’s tires were in good condition.

Driving in snow is tricky, even if you think you’re good at it.

Snowy roads are hazardous, and the most seasoned drivers and best-equipped vehicles can get into trouble on them. Marc Lacey, national editor of The New York Times, saw ample evidence of that as he drove 360 miles through the storm on Sunday from Buffalo to New Jersey by way of Central New York and northeastern Pennsylvania:

I knew it was a particularly fierce ice storm, and not a run-of-the-mill one, when I spotted an upended salt truck, a big sturdy vehicle that slid off the road outside of Buffalo and had flipped on its side on the shoulder. Call that Accident No. 1. Over the course of the day on Sunday, I would count no fewer than 24 accidents. There was the car turned the wrong way on the expressway on-ramp — Accident No. 2. There was the car turned sideways — Accident No. 3. There was the three-car pile up. The four-car pile up. One car had gone off the road, down a gully and up the other side. I could not interview any of the drivers, some of whom were still on the scene, as I too was navigating the storm and struggling to remain between the lines. The airports were nightmarish, I am told, with flights delayed and passengers stranded in the post-Thanksgiving rush. But the roads, I dare say, were worse.

Experts say that factors like a few degrees’ difference in temperature, uneven application of road salt or the recent passage of another vehicle can make one patch of pavement much slipperier than another a few feet away. Falling or blowing snow can make it especially hard to tell where the slick spots are. And for drivers, familiarity can breed complacency.

“We see a lot of people from all over the country who have grown up in the Snow Belt and have years and years of driving experience, and in reality have just been lucky, because their technique leaves a lot to be desired,” Mark Cox, the director of the Bridgestone Winter Driving School in Steamboat Springs, Colo., told The Times in January.