Heavy snows belted the Western mountain regions of the country yesterday, snarling Thanksgiving Day air traffic in Denver and causing a 40-car pileup on a busy interstate highway in Utah that injured 20 people.

Up to 18 inches of snow was forecast yesterday in the southern and central Rockies, the National Weather Service said.

Meanwhile, in the Northeast, portions of New York, Vermont and New Hampshire received heavy snow.

As much as 10 to 14 inches fell in central and northeast Vermont and in New Hampshire, as much as 13 inches of snow was reported at Big Diamond Pond.

Snow fell across upstate New York and northern New England Thursday afternoon. Maine received 13 inches at Eaustis and Flagstaff Lake, and up to 14 inches were reported in parts of upstate New York.

A winter storm warning has been posted for southwest Kansas.

In the West, a slow-moving storm dropped up to a foot of snow in some parts of Colorado for Thanksgiving, creating major delays for holiday travelers at Denver's Stapleton International Airport. Inbound flights were delayed as much as three hours, and outbound flights were departing 90 minutes late, an airport spokesman said.

Blowing snow and bumper-to-bumper traffic near Cedar City, Utah, touched off a 40-car pileup Wednesday night on Interstate-15. About 20 people were injured, two critically, and hundreds of Thanksgiving Eve travelers were delayed for hours, police said.