Sea-Tac Airport runways close due to ice; hundreds of flights canceled throughout the day

Hundreds of flights at Seattle-Tacoma International Airport were canceled Friday morning and throughout the day due to icy conditions on the runways. 

According to FlightAware, Sea-Tac had nearly 500 cancelations. 

At about 5 a.m., airport officials said it had to close its runways indefinitely to de-ice the surfaces. 

"Safety is our priority before we can reopen the runways," officials tweeted.

Seattle-based Alaska Airlines had to cancel all of its Alaska and Horizon flights in and out of Seattle and Portland before noon. 

Crews continued to clear the runway after 9 a.m.

The airport is advising travelers to check with their airline for updates on their specific flights.