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 200 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.

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.

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

A 200-mile stretch of I-70, the main east-west highway through the state, was closed from Denver to Colby, Kan. Greyhound canceled all bus trips out of Denver.

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.

At the airport, check-in counters that had been packed Thursday with travelers rushing to beat the storm had normal lines Friday morning.

Chris Malmay of San Diego hoped to spend a long holiday with family in Colorado, but because of the first storm, he could not reach Denver until Christmas Eve. On Thursday, his flight back to California was canceled because of the second storm.

"It's been crazy," Malmay said as he waited to board a plane Friday. "I'm saying, 'Please let me go back where it's sunny. You won't get snowed in, I promise."'

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, I-40 was closed from Albuquerque to Santa Rosa, and numerous crashes were reported, after a storm swept through.

More than an inch of snow per hour fell Friday morning in Kansas. Forecasters predicted 15 to 20 inches in some areas.

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.

Contributing: Dan Elliott, Don Mitchell, Ben Neary