NEW YORK – A storm that already snarled Thanksgiving travel across much of the country threatened to dump a foot and a half of snow on parts of the East, leading governments to close schools and offices, canceling or delaying hundreds of flights, and sending an army of salt trucks scrambling to coat roads.

The storm dumped one round of snow on parts of the region late Sunday and could drop 10 to 20 inches total by Tuesday morning from Pennsylvania to Maine, forecasters said. Heavy snow was also expected in the Appalachian Mountains down to Tennessee and North Carolina.

Alana Kirkpatrick didn’t enjoy her 5 a.m. “workout” in Nashua, New Hampshire, which consisted of removing heaps of snow from her car.

“Why do I still live in New England?” she said.

Hundreds of schools were already closed, with more snow on the way.

“It’s going to be a long, difficult storm,” Gov. Chris Sununu said.

In areas not already bludgeoned by the first wave, schools closed preemptively as rain was expected to turn into snow in the region’s first significant storm of the season, a nor’easter so named because the winds typically come from the northeast.

Inland areas appeared to be in for the worst snow, with the forecast in Albany, New York, predicting 6 to 14 inches. At least four counties closed schools Monday in West Virginia, where 2 inches to a foot of snow was forecast.

Closer to the heavily populated, coastal Interstate 95 corridor, a wintry mix was more likely.

Only 3 inches of snow was forecast for New York City, where schools were expected to remain open, and 5 inches for Philadelphia. Up to 9 inches, though, was possible in Boston by Tuesday night.

New York Gov. Andrew Cuomo told nonessential state employees to stay home Monday, and New Jersey Gov. Phil Murphy decided to close government offices for nonessential employees at noon.

More than 340 flights into or out of the U.S. were canceled Monday morning, with more than 1,500 delays. Airports in the New York and Boston areas accounted for many of them.

Tractor-trailers were banned or lower speed limits put in place on stretches of highway in New Jersey and Pennsylvania. New York also posted lower speed limits on some highways.

Many buses from New York City to Pennsylvania and upstate destinations such as Ithaca and Binghamton were canceled.

Dozens of school districts in upstate New York were closed Monday, along with several State University of New York campuses and other colleges.

A commuter ferry on its way to Boston, where it was rainy and windy Monday morning, hit a wave and listed heavily, sending some passengers to the floor. No injuries were reported.

The trouble began in the East on Sunday as the storm moved out of the Midwest.

State police had responded to more than 550 storm-related crashes across New York by 7 p.m. Icy roads caused crashes on Interstate 84 in Pennsylvania, and ice closed part of Interstate 81 near Binghamton, New York, for a time.

The same storm has pummeled the U.S. for days as it moved cross country, dumping heavy snow from California to the Midwest and inundating other areas with rain.

Duluth, Minnesota, is cleaning up more than 21 inches of snow. Major highways reopened in Wyoming and Colorado after blizzard conditions and drifting snow blocked them.