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More than 480 flights at Denver International Airport were delayed and as many as 15 were canceled Monday, according to FlightAware.com data. Airport officials in Denver initially said the delays were due to smoke and haze in the Denver metro area — and said most of the later delays were due to weather issues in other parts of the country, CBS Denver reports.

The delays in Denver were caused by the planes having to be spaced out due to visibility, according to Alex Renteria, public information officer for the airport.

Renteria said a Federal Aviation Administration traffic management program was being used to manage arriving flights. On Monday afternoon, Renteria clarified the traffic management program only lasted from 8:46-9:11 a.m.

“The majority of our delays after that were/are due to weather around the nation,” Renteria explained.

A view of the Denver-area skyline earlier on Monday, July 19, 2021.

CBS Denver

There are two large wildfires burning in northwestern Colorado — and dozens of active wildfires in California, Oregon, Washington, Idaho and Montana — but the smoke in the Denver metro area is no worse than it has been, Altieri said.

Altieri checked the automated equipment at the airport in Denver at 10:45 a.m. and it was not indicating any visibility issues that would hamper flights. The FAA website did not show any issues for DIA on Monday morning, and the National Weather Service was not aware of any problems related to smoke and haze.  

Altieri said the smoke was expected to get worse in the afternoon, but would still not be in the “red zone.”