Alaska Airlines had an outage in Seattle on Sunday morning that left flights grounded.

Some flights still showed as on time, leaving passengers confused about whether flights had been canceled.

As of early Sunday, 5 flights had been canceled and 27 were delayed because of the outage, an Alaska Airlines representative told Business Insider.

Some passengers were headed to a big consumer electronics conference called CES in Las Vegas, and others were headed to JPMorgan's healthcare conference in San Francisco.

Alaska Airlines halted flights on Sunday morning, leaving customers stuck at the airport, after a national outage that began at 3:30 a.m. Pacific time and ended at 5:15 a.m.

The airline stopped some customers from boarding flights, and gate agents weren't sure when flights would resume.

A representative for Alaska Airlines told Business Insider that the outage took place in the airline's Seattle office, impacting the operations system and causing the airline to ground flights.

The representative on Sunday morning said five flights were canceled and 27 were delayed because of the outage.

The outage likely occurred because of high winds in Seattle.

The delays and cancellations are affecting travelers heading to the annual Consumer Electrics Show in Las Vegas and the J.P. Morgan Healthcare Conference in San Francisco, including Business Insider reporters.