Denver ? Denver’s second big snowstorm of the holidays grounded scores of flights Friday during one of the busiest travel periods of the year and blanketed streets that never got plowed the last time.

At Denver International, the nation’s fifth-busiest airport, the major airlines canceled 15 percent to 20 percent of their flights Friday – nearly 300 departures – to ease congestion.

But officials were optimistic they would avoid a rerun of the pre-Christmas blizzard that unloaded 2 feet of snow and shut down the vaunted “all-weather” airport for two days, stranding 4,700 passengers and snarling holiday travel around the country.

The latest storm hit the state Thursday morning, and the snow was expected to be spread out over two or three days, making it easier for plows to keep up. A foot or more of snow was forecast in Denver through today.

“That’s something we can handle,” Frontier Airlines spokesman Joe Hodas said.

The storm eased in the Denver area Friday afternoon but continued to buffet the Plains as it moved east.

Winter storm warnings extended from New Mexico to South Dakota, and blizzard conditions were forecast for the eastern Colorado plains and parts of southwestern Nebraska, western Kansas and the Texas and Oklahoma panhandles.

A weather slowdown at Denver has relatively little nationwide ripple effect on airlines other than United and Frontier, which account for 80 percent of Denver’s traffic, said David Castelveter of the Air Transport Association, an industry group.

Ellen Berman takes the opportunity to snowshoe Friday on a street in Boulder, Colo. Winter storm warnings were in effect in New Mexico and South Dakota, and blizzard conditions were forecast for parts of Colorado, Nebraska, Kansas, Texas and Oklahoma.

The New Year’s weekend was extended by a day Friday as government offices and businesses closed in Denver and other Colorado cities.

Colorado Gov. Bill Owens again declared a state of emergency, putting the National Guard on standby. During the previous storm, troops rescued motorists and delivered diapers, blankets and baby formula to stranded travelers at the airport.

A tow truck driver was killed when a car slid off I-70 Thursday night near Burlington, about 150 miles southeast of Denver.

The storm stretched across the Rocky Mountains into the western Plains, where forecasters warned that the gusts could whip up blinding whiteouts.

In New Mexico, Interstate 40 was closed from Albuquerque to Santa Rosa, and numerous crashes were reported.

The 7 inches of snow that had fallen in Cheyenne, Wyo., by Friday morning gave the city 24 inches total in December, topping its nearly century-old record of 21.4 inches for the month.