Overview
- Roughly 55,000 to 60,000 customers lost power beginning around 12:45 pm local time across Casper, Rapid City and nearby communities.
- Black Hills Energy said the disruption originated at a transmission facility outside its system, with the precise cause still under investigation.
- Rocky Mountain Power posted an estimated restoration time of 9:45 pm Thursday as crews worked to stabilize the grid.
- Officials noted the Dave Johnston Power Plant fire was reported after the rolling outages, reducing the likelihood it triggered the blackout.
- Wyoming homeland security officials said geomagnetic activity is being evaluated as a possible contributing factor while residents reported brief, intermittent restorations.