Fourteen flights headed to Denver International Airport were diverted to Colorado Springs because of strong winds and microbursts.
According to the National Weather Service, a microburst is a "downdrift (sinking air) in a thunderstorm" which can cause comparable damage to tornadoes in some cases, and pose a "significant threat to aviation."
Three other flights were diverted to other airports.
All of the flights were from United, American, Frontier and Southwest.
The final flight was expected to leave Colorado Springs just before 10 Friday night.