A multistate power outage Thursday left as many as 95,000 customers in Wyoming without electricity, according to some reports, and may have caused a fire at the Dave Johnston coal-fired power plant near Glenrock.
The outages affected more than 10% of Wyoming customers and extended into portions of western South Dakota, according to reports.
“We believe the outage, which began around 12:45 p.m., was triggered by two tripped 500-kilovolt lines near Medicine Bow, Wyoming,” Western Area Power Administration Public Affairs Specialist Stephen J. Collier said in a statement. “This incident resulted in an abnormal voltage event that subsequently tripped a number of surrounding lines, including WAPA transmission, resulting in further power outages to communities across the area.”
By 4:30 p.m., electricity was restored to about half of the affected customers, according to PowerOutage.us. But officials warned that power delivery could remain unstable.
Authorities were searching for correlations between the events, according to Wyoming Department of Homeland Security Director Lynn Budd, while utility workers were gradually restoring power to impacted communities around the state.
The widespread outage was highly unusual, because it affected several different electrical utility providers, including Rocky Mountain Power, Black Hills Energy and Montana-Dakota Utilities customers. The affected utilities share an interconnected grid.
The fire at Dave Johnston started after the power outage, Budd said. The agency reiterated that because the Dave Johnston power plant fire happened after the power outage, the fire was a “possible consequence of the power outage, not the cause.”
WyoFile was waiting on more information from the Converse County Emergency Management office — though an official in that office reached at 3:30 p.m. said the fire had been put out. There were no emergency vehicles visible just outside the entry gate to the Dave Johnston coal-fired power plant shortly after 2 p.m.
A liquor store in Glenrock temporarily closed due to widespread power outages. (Dustin Bleizeffer/WyoFile)
Outages were reported in Gillette, Casper, Douglas, Newcastle and Sheridan, among other communities in Wyoming. Natrona County took the biggest hit, according to PowerOutage.us, which tracks electricity disruptions.
Rocky Mountain Power reported 55 outages in Wyoming affecting 56,776 customers around 2 p.m.
Powder River Energy Corporation, which serves Campbell, Crook, Johnson, Sheridan and Weston counties, reported 26,544 customers experiencing outages.
Intermittent outages persisted in some Wyoming communities throughout Thursday afternoon.
“Bottom line, members should be prepared for an extended outage through the night. The voltages coming into our system are unstable and are tripping off power,” Powder River Energy Corporation wrote on its Facebook page shortly after 3:30 p.m. Thursday. “That’s why some are seeing ‘lights on, lights off’. We have crews staged at almost every substation to begin safe restoration of power once the voltages stabilize. However, we do not want to flip the switches unsafely. We do not want to blow up transformers or arrestors and cause more problems.”
Electric transmission lines stretch from a wind energy facility north of Medicine Bow on July 1, 2022. (Dustin Bleizeffer/WyoFile)
In Gillette, the city government reported a community-wide outage at 12:40 p.m. An hour later, the city posted on its Facebook page that power had been restored. Things changed again 40 minutes later.
“As of approximately 2:20 p.m., all of the City is out of service again,” an updated post read. “We are being affected by a widespread regional outage and do not have an expected return to service at this time.”
The outage in Casper appeared city-wide, the police department there reported. The agency directed people who were dependent on oxygen and in need of electricity to two locations in the city.
Natrona County’s library and YMCA closed early due to the outages, and several local businesses reported the same. The Natrona County School District canceled all after-school activities, according to a text sent to parents.
Some businesses, including a liquor store, in Glenrock — just a few miles from the Dave Johnston plant — posted written signs that they were temporarily closed due to the power outages. Non-essential Natrona County offices closed for the remainder of the business day. The city of Casper announced that a number of its facilities — including City Hall, Casper Recreation Center, Casper Ice Arena, Casper Family Aquatic Center, and Fort Casper — closed early and would not reopen until Friday due to the unstable electricity.
Suggested safety precautions
Treat all downed power lines as live and extremely dangerous. Stay away and report them immediately to 911 and your local utility provider.
- Conserve cell phone battery: Limit non-essential calls and use text messaging where possible. Utilize cell phone carriers or public safety radio for emergency communication.
- Use generators safely: If operating a portable generator, NEVER run it inside a home, garage, or any enclosed space. Ensure proper ventilation to prevent carbon monoxide poisoning.
- Check on neighbors: Check on vulnerable family members, neighbors, and friends, particularly the elderly or those dependent on electricity for medical equipment.
- Use alternate facilities: Residents who are oxygen-dependent or require power for life-sustaining medical equipment and do not have backup power are encouraged to contact their local emergency management office or visit designated facilities.
- Avoid overloading circuits: Once power is restored, gradually turn on appliances to prevent overloading the local circuits.
