Alaska Air Group resumed flights after a data center hardware failure triggered a major IT outage, grounding its entire fleet for hours. The issue caused over 150 flight cancellations and disrupted operations across Alaska Airlines and Horizon Air.

Alaska Airlines is rushing to fix a major disruption to its service after a hardware failure forced a ground stop of its planes for around three hours Sunday night.

As of about 7 a.m. Monday, 56 Alaska Airlines and Horizon Air flights had been canceled at the airport and 62 had been delayed.