Major Blackout Affects Wyoming And Western South Dakota

A widespread power outage swept across multiple states Thursday, cutting electricity to an estimated 95,000 Wyoming customers and possibly sparking a fire at the Dave Johnston coal-fired power plant near Glenrock.

The blackout affected more than 10% of Wyoming utility customers and stretched into western South Dakota. According to the Western Area Power Administration, the disruption began around 12:45 p.m. when two major 500-kilovolt transmission lines near Medicine Bow tripped, triggering an abnormal voltage event that cascaded across the regional grid and shut down additional lines.

By 4:30 p.m., about half of those affected had power restored, though officials warned the system remained unstable. Multiple utilities were impacted — including Rocky Mountain Power, Black Hills Energy an