East Texas Medical Center had to run on generator power for about two hours after Wednesday's storm knocked out power.
The hospital went on full divert at 6:07 p.m., said hospital spokeswoman Rebecca Berkley, and the power had been restored fully by 7:58 p.m. During the outage, the hospital was not admitting patients through its emergency room, and they were instead taken to other facilities for treatment.
Ms. Berkley said there were lightning strikes in the area that could have caused the loss in power.
The generators can power the entire hospital, and patients were not expected to have any interruptions in care.
Oncor spokesman Charles Hill said as of late Wednesday, there were no major outages in the city of Tyler.