DENVER -- The winter storm that pounded most of Colorado on Tuesday was so severe that virtually all flights from Denver International Airport were canceled after noon, leaving about 1,000 people without a place to go for the night.

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United, American, Frontier and America West announced cancellations after weather conditions began to deteriorate. Blowing snow and the heavy downpour that occurred after 2 p.m. caused blizzardlike conditions and poor visibility. Other airlines quickly followed suit and started rebooking their passengers for other flights.

DIA representatives insist that the "all-weather airport" is still open for business but for all intents and purposes, there is no reason for any traveler to head to the airport.

Passengers who have sat on planes for hours, waiting to depart from the tarmac were frustrated.

Alan McKennan, a passenger on United's Flight 1557 to Phoenix, said his plane sat on the tarmac for from 11 a.m. to just after 6 p.m.

"We've just been sitting on the aircraft just enjoying each other's breath, I guess," McKennan said. "It's been very frustrating. Unfortunately, there was nothing that United could do about the nasty weather, but the fact that they left their valuable customers sitting on the planes for seven hours is obviously disappointing."

McKennan didn't want to travel to Phoenix and was ready to head home and fortunately, he only had a carry-on luggage.

Passengers who called their airlines earlier in the day and learned that there were no delays or cancellations until they got to the airport were also upset.

United had said earlier that it was only cancelling half of its flights but now the airline has canceled all flights until noon Wednesday.

More flight cancellations can be expected for Wednesday since this storm system stay strong and steady and will not end until Thursday morning, 7NEWS reported.

Motels and hotels near the airport report that they are booked up for the night so DIA handed out blankets, pillows and cots to the passengers who were planning to camp out at the airport.

The airport and the Denver Metro Convention and Visitors Bureau also bused some stranded passengers to the Adam's Mark Hotel in downtown Denver.

It is not known when flight schedules will be back to normal, but most airlines report that it may take a day or two after a severe storm to get all the planes and people in the right place, 7NEWS reported.

The best thing to do if you are checking on a flight for Wednesday or Thursday is to call the airline. United's number is (800) 824-6200. You can also check the status of your flight at United.com.

"The bad weather in the area -- snow and wind -- does not allow us to operate the full schedule. Customers are even having difficulty getting to and from the airport," said Larry De Shon, senior vice president of United's airport operations.

Traffic to and from the airport was slow and at times treacherous because of the blizzard conditions. Pena Boulevard was down to one lane in each direction. Pena was snowpacked and icy with poor visibility.

During the blizzard of 1997, thousands of travelers were stranded at DIA when planes were grounded. Airline carriers reported $20 million in losses and the mayor came under sharp criticism for deciding to keep the airport open. A state of emergency was declared.