Thousands of homes across Northwest Montana were without power Friday morning due to a fault in a key transmission line.

According to a media release from Wendy Ostrom Price at Flathead Electric Cooperative, about 16,500 Co-op members experienced the outage shortly after 6 a.m. The blackout occurred after a fault on a Bonneville Power Administration transmission line that runs from Kerr Dam, north to Columbia Heights and then west to Trego.

Other co-ops, such as Mission Valley and Lincoln Electric, were also affected, Ostrom Price said.

Nearly all of the outages were reversed by 9 a.m., according to the co-op’s online outage map.

The transmission line impacted seven of the co-op’s distribution substations. A Bonneville Power spokesperson said the disturbance on the transmission line was caused by equipment failure.

Ostrom Price said Bonneville — the co-op’s wholesale power supplier — responded very quickly and was able to restore power to most members within an hour and a half.