A hardware failure at an Alaska Airlines data center caused a system-wide “ground stop of flights” on Sunday night, the airline said. The airline has canceled more than 150 flights at various airports, including 64 Monday morning, with additional flight disruptions expected.

"At approximately 8 p.m. Pacific on Sunday, Alaska Airlines experienced an IT outage that’s impacting our operations. We requested a temporary, system-wide ground stop for Alaska and Horizon Air flights until the issue is resolved," the airline said in a statement Sunday evening. The airline said it resumed operations at about 11 p.m. PT.

Alaska Airlines warned of more flight disruptions on Monday after an unexpected failure of a critical piece of hardware at its data centers late Sunday forced it to halt all flights for about three hours.