Customers of internet and cell service provider GCI lost service around the state after a Monday morning power outage in Anchorage.

The loss was caused by the failure first of an electrical transformer — belonging to Anchorage’s city-owned utility Municipal Light and Power — then of a GCI backup power system.

The transformer, located in midtown Anchorage, failed around 4:45 a.m, leaving GCI’s headquarters in the nearby Denali Towers without commercial power.

ML&P crews finished replacing the transformer around 1 p.m, according to updates the utility posted on its Facebook page.

The headquarters has “dual backup power systems,” GCI spokesperson Heather Handyside wrote in an email, consisting of generators that serve a “substantial battery plant that can keep network equipment running for several hours.”

“In this case the system kicked on as planned, but after a few hours there was a point of failure in one of the pieces of equipment, and we lost power,” Handyside said.

The backup power system had been successfully tested on July 3 and GCI will be investigating its failure, Handyside said.

GCI announced the outage on Facebook around 8 a.m.

Wireless service and local and long-distance calling went down statewide. Internet outages appeared “to be localized in Anchorage,” Handyside said, and some customers had cable interruptions in southeast Alaska.

GCI had restored wireless, local, and long-distance service by 3:15 p.m and all services by 4:16 p.m, according to emails from the company.

Handyside said the Anchorage internet outage affected around 10,000 customers.

As of Monday afternoon, GCI hadn’t estimated the number affected by the statewide wireless outages.

For those seeking credit in their billing for the loss of service, Handyside said “they can contact our service desk and talk through the interruptions they’ve experienced so we can make that determination.”

Reach Ben Boettger at bboettger@peninsulaclarion.com