Denver International Airport has canceled about 500 flights Tuesday morning and hundreds of other flights have been delayed on average nearly four hours, officials say.

The snowstorm dropped 7.7 inches of snow at DIA., according to the National Weather Service.

Gusting winds and reduced visibility added to the delays. The average delay for departures was nearly four hours according to DIA spokeswoman Mindy Crane..

It could take about a day to clear out any snow-related backlog, said Jeff Price, an aviation security expert and professor of aviation at the Metropolitan State University of Denver.

“The airlines, unfortunately, almost tend to overbook themselves constantly these days, so there’s not a lot of room,” he said.

If airlines run out room to squeeze passengers in on upcoming scheduled flights, some will bring in additional aircraft to bolster their fleets, he said. Denver could be in a good position in that regard, he said.

“We have Southwest, United and Frontier that all hub here, two with maintenance facilities (here),” he said. “In a city with three hubbing airlines, that actually benefits everyone.”

“The delays are just building and building and building,” he said.

Despite the heavy snow, most flights at DIA have not been canceled, Crane pointed out.

“We’re keeping aircraft moving,” he said.

Pena Boulevard was briefly closed in both directions at about 5:20 a.m. because of a traffic accident, said Heath Montgomery, DIA spokesman.

That accident was cleared but caused additional backups as snow plows cleared the roads. Motorists should expect winter conditions and plan for extra travel time out to the airport.

“People should definitely check their flights. That’s extremely important,” Crane said.

Passengers can check their flight status with their airline or at www.FlyDenver.com.

Snow-removal crews were deployed overnight and remain active for the duration of the snow, Crane said.

DIA has more than 250 pieces of airside snow removal equipment, 110 pieces of equipment for landside parking lots and roadways, and more than 500 trained snow-removal personnel.

The equipment being deployed for this storm includes blowers, brooms, blades, plows, runway sanders, 4,000 gallon chemical trucks, loaders with box plows and snow melters, the news release says.

The airlines are expected to be in full de-icing operations, so passengers should expect to spend a little extra time on the aircraft prior to departure. The average de-icing time is approximately 16 minutes, but can vary based on the type of aircraft.

Kirk Mitchell: 303-954-1206, kmitchell@denverpost.com or @kirkmitchell or denverpost.com/coldcases