More than seven inches are on the ground and as many as 18 inches are expected overnight. The heavy snow forced officials to close Interstate 25, about 60 miles north of the city near Wyoming.
Gov. Bill Owens again declared a statewide disaster emergency, just a week after a pre-Christmas blizzard shut the airport for two days, stranded 4,700 holiday travelers and backed up flights around the country.
The broad storm stretched from the Rocky Mountains into the western Plains; winter storm warnings were in effect for parts of Colorado, Wyoming, western Nebraska and Kansas, New Mexico and the Texas Panhandle.
CBS News correspondent Kelly Cobiella reports that lines at Denver International Airport were much longer than most ticket-buyers were expecting, and that even having a ticket was no guarantee of a quick getaway. Though the airport is still open, most evening flights — more than 200 — have been canceled as the snow continues to fall.
Airline industry analyst Michael Boyd says a lack of planning was part of the reason thousands of passengers got stranded at the Denver airport last week. Another factor: The airlines are doing such good business these days that there are few seats available on a new flight after one is cancelled.
Earlier Thursday, managers at Denver International Airport — the nation's sixth-busiest airport, according to the Airports Council International-North America — drew up snowplowing plans, and airlines urged ticket-holders to flee Denver early or delay departures until after the storm. By 2 p.m. United Airlines and Frontier, which together account for 80 percent of traffic at Denver International Airport, canceled more than 180 flights.
But airport spokesman Chuck Cannon promises it will be different this time.
"We are going to focus a little differently, on maybe getting some of the ramp areas, the areas between the concourses where the planes park and get to the gate, we're going to try to get those cleaned a little sooner than we did last time," Cannon told CBS Radio News.
Many Colorado cities were still trying to recover from last week's storm, chipping away at the thick ice and packed snow that layered some streets while repairing broken plows and stockpiling materials for the next wave.
"Believe it or not, the first storm is not over for us," said Saleem Khattak, streets manager for Colorado Springs' Public Works Department.
Twenty of the state Transportation Department's 900 plows broke down during last week's storm. Ten have been repaired, but the others might not be ready, department spokeswoman Stacey Stegman said.
Last week's storm virtually shut down life along the Front Range, the 170-mile corridor along the foot of the Rockies that's home to 3.8 million people in Denver, Colorado Springs and other cities. The storm dropped up to 3½ feet of snow in the mountains and two feet on the Front Range.
Denver International Airport was closed to all flights for 45 hours, leaving about 4,700 people to try to sleep in the airport on the first night. Highways, schools and businesses closed — and even the mail couldn't get through.
Denver and airport officials have been fending off criticism of their snow-removal efforts almost since the storm hit.
"Obviously, we had to close the airport. We didn't like that, but when you get an inch and a-half of snow per hour and 40-mile-an-hour winds and drifts up to 12 feet deep on your runways, you just can't operate safely," Cannon said.
Ray Szalay, who missed his flight home to Cleveland after getting stuck in traffic on Interstate 70, grabbed his best chance — a ticket for Houston, where he hoped to find a connecting flight.
After running out of bedding for stranded passengers during the first storm, airport managers lined up cots and blankets and urged food vendors to ensure they had plenty of supplies on hand.
In Denver, plows drenched streets with de-icer, offices closed early and residents stocked up on groceries in preparation for the storm.
Ace Hardware in Longmont sold 260 snow shovels - its entire stock - in the first three hours it was open Thursday, cashier Ryan Goforth said.
Federal courts closed early, as did many government offices and businesses in Denver and other cities in the state's main population corridor along the Rocky Mountain Front Range.
Residents of Cheyenne, Wyo., also braced for the second snowstorm to hit the area in a week. Heavy snow began falling around dusk, and forecasters said up to a foot was expected.
In California, another powerful winter storm left tens of thousands of people without power on Thursday as winds gusted to near-hurricane force and blowing snow closed a stretch of Interstate 5 in the mountains north of Los Angeles for 11 hours. It reopened Thursday morning.
Forecasters in California warned of dangerous winds, with gusts over 80 mph, in the region's valleys and mountain passes.