Alaska Airlines said it has requested a ground stop for its fleet and that of regional subsidiary Horizon Air amid a computer system outage Sunday night.

The request to federal authorities would keep Alaska and Horizon flights out of the air until the system is returned to normal operations, Alaska said in a statement.

It said the outage involves its information technology network. It is “impacting our operations,” Alaska said.

“We are experiencing issues with our IT systems. We apologize for the inconvenience and are working to resolve the issues,” read a message on the airline’s website.

Even if the problem is resolved Sunday, there could be lingering effects as the airline tries to get flights back on schedule, Alaska said.

“There will be residual impacts to our operation throughout the evening,” it said.

Alaska and Horizon Air ticket holders were asked to check the statuses of their flights before they arrived at their departure points.

It was one year ago nearly to the day that the cybersecurity company CrowdStrike’s sensor configuration update to its widely used platform triggered a system crash that affected airlines, medical facilities, businesses and police forces around the globe, with Microsoft computers showing “blue screens of death.”

The exact cause of Sunday’s Alaska outage was not immediately clear.

This is a developing story. Please check back for updates.