The news wasn't comforting: While some flight updates still said "on time," airport spokesman Steve Snyder said the runways likely wouldn't open before noon Friday.
The airport crews simply can't keep up with the falling and drifting snow, Snyder said. They plow the runways, but within 30 minutes, the tarmacs are covered again.
"It feels like I'm a refugee," said Lisa Maurer, a University of Wyoming student who was stuck at the Denver airport as she tried to make her way home to Germany. About 4,700 people hunkered down with her overnight after all flights there were canceled -- more than 1,000 of them Wednesday and Thursday morning alone.
Denver's streets were empty, and long stretches of highway in the eastern Colorado were so impassable, even the mail couldn't get through. Bus and light rail service in a six-county region was suspended.
The Colorado Avalanche postponed Thursday night's hockey game against the Calgary Flames. Wednesday night's basketball game between the Denver Nuggets and Phoenix Suns was also called off.
Cathy Stuart, 44, a sales representative from Dallas, spent the night on the airport's stone floor after her flight home was canceled.
"I don't feel bad, but I just want to get out of here," she said.
More than 3 feet of snow had fallen in some mountain areas since Wednesday morning, and up to 25 inches fell in the Denver metro area, including 2 more inches on Thursday.
A snowstorm also dumped up to 18 inches on New Mexico, icing roads and closing schools, and the National Weather Service warned that another storm was heading for New Mexico.
Heavy snow also fell on southeastern Wyoming on Wednesday closing interstate highways, stranding travelers and sending government workers home early in Cheyenne.
The amount of snow was hard to measure because it wasn't evenly distributed. "We have drifts up to 6 feet high in some locations, and in other areas, it is completely dry on the asphalt and concrete," said Mike Sowko, a forecaster with the National Weather Service in Cheyenne.
In Denver, Colorado Springs and other cities along the Rocky Mountain Front Range, workers slipped and slid their way home on Wednesday and stayed there, leaving the cities virtual ghost towns Thursday, typically a busy shopping day. A few pedestrians trudging down the middle of unplowed streets as the snow continued.
Three more inches of wind-whipped snow was expected Thursday before tapering off in the afternoon. Parts of Nebraska and Kansas were also getting snow and ice, but farther east, warmer temperatures meant even Chicago was only forecast to get heavy rain as the storm moved through.
Colorado Gov. Bill Owens declared a state of emergency and activated the National Guard, which assisted dozens of motorists on the highways around Denver and delivered diapers, formula and bottled water to Denver's airport.
Long stretches of Interstates 70, 25 and 76, major east-west and north-south routes through the Mountain West, were closed.
National Guard and sheriff's deputies rescued about 50 people overnight from snowbound vehicles in Weld County, where up to 22 inches of snow fell. About 18 others were still stuck in their cars Thursday morning, said Weld County emergency management director Roy Rudisill. In the Denver suburb of Broomfield, police rescued nearly 100 people stranded in cars along U.S. 36, the main route between Denver and Boulder.
"It's just amazing how many people are still out there," said Robert Thompson, spokesman for a local American Red Cross chapter.
"They pulled everyone off the highway," said Leon Medina, manager of a truck stop on Interstate 25 in Walsenburg, about 130 miles south of Denver. "Cars are all around the building. Trucks are all over, trucks and cars pulled into ditches."
Weather Service program manager Byron Louis said it was the most powerful storm to hit Colorado since March 2003, when a blizzard dumped up to 11 feet of snow in the mountains over several days and was blamed for at least six deaths.
Mail service was canceled in the eastern half of the state because mail carriers and trucks delivering mail four days before Christmas couldn't get through.
"We don't want to take the risk of clogging up the system just by being out there," said Al DeSarro, a U.S. Postal Service spokesman in Denver. "We're considering delivering on Sunday to make up for what's sure to be a backlog of mail."
At Denver International Airport, a major hub for United Airlines, United canceled more than 670 inbound flights, plus 160 that had been scheduled leave before noon Thursday. Frontier Airlines canceled up to 190 flights.
"It's the wind and blowing and drifting snow that is causing the main problems," Snyder said.
Some airport monitors tantalized travelers by listing "on time" beside arrivals and departures, but Snyder said that was probably caused by a computer glitch.
"I'm just happy to be alive. It was a terrifying drive," Sara Kelton said of the two-hour crawl over slick, snow-clogged roads to reach the airport.
Public transit service was not expected to resume until late Thursday at the earliest.
"It was comical for a while," said bus rider Matt Notter of Boulder. "Then we realized, this is an all-night thing."
