PORTLAND, Ore. (KOIN) — Alaska Airlines announced that all Alaska and Horizon flights to and from Portland are canceled while it’s “thinning” flight schedules in Seattle.

If the weather doesn’t improve, the airline said more cancellations and delays are likely.

In addition to 550 Alaska Airlines flights being cancelled nationwide, Alaska said it canceled 270 flights scheduled in Portland and Seattle.

According to FlyPDX, 121 departing flights and 114 arriving flights from various airlines have been canceled as of 9:30 a.m. The airline has also cancelled all PDX flights for the evening, officials said, with no estimated time for when flights will be back in the air – noting it could take several days for passengers to get a new flight.

“Travelers should not head to the airport if their flight has been cancelled. We prefer that travelers remain safely at home and call their airline to reschedule their flight. When flight schedules are impacted, we understand wait times can be long on the phone; travelers are advised to use the airline’s app or website in addition to calling,” PDX told KOIN 6 News Friday morning.

On Friday morning, PDX said crews have been working to clear runways and spot treatments in parking areas.

Early Friday morning, the Seattle-Tacoma International Airport tweeted that its runways are closed indefinitely. The airport said it’s working to de-ice surfaces, which crews have been busy doing so the last few days.

The Portland and Seattle areas are under winter weather advisories.

Sharon O’ Hare and her husband Mike were flying Alaska Air to New Mexico. Now, their Christmas plans are re-routed to Portland.

“We’re very stranded. We’re stranded for four days,” O’ Hare told KOIN 6 News. “Now we’re looking for a place to stay in Portland.”

Another stranded traveler, Shonda Redmyne who lives in Scotland, is trying to get home to her family by Christmas.

“I’ve only got as far as Portland. I’m supposed to go to the Isle Arran, I’m not going to get home in time for the last ferry before Christmas, I won’t get home until the 26th,” Redmyne said. “You’ve just got to say, ‘it will be over eventually,’…Christmas will be another day.”