UPDATE 3:15 p.m.: This story has been updated to reflect power is being returned to some areas, with the number of customers affected down from 93,000 to about 70,000.
The Dave Johnston Power Plant in Converse County was on fire early Thursday afternoon — but that came after, not before, rolling power outages throughout the state, Converse County Emergency Management coordinator Russ Dalgarn told Cowboy State Daily.
Converse, Natrona, Goshen, and Platte Counties, and northeast Wyoming, suffered power outages Thursday afternoon, Wyoming Department of Homeland Security Director Lynn Budd confirmed to Cowboy State Daily.
The outages had affected nearly 93,000 customers at one point, but by 3:15 p.m. power was being restored across the region and customers without power was down to about 70,000, according to the tracking website PowerOutage.us.
Fremont County experienced outages in spots and flickers.
The aurora borealis that unfurled across the northern hemisphere this midweek could be a cause, Budd said, though she said she did not know a cause for certain.
“It’s something we’ve considered — but we’re at the lower cycle of that,” said Budd. “It could just be cascading consequences of cascading outages.”
She confirmed the Dave Johnston Power Plant was on fire.
During a phone call with Dalgarn at about 2:20 p.m., he said he’d just learned the fire was out and everyone at the plant was accounted for.
Dalgarn was driving back quickly from Cheyenne to his home county “to figure out what the hell is going on,” since no one in his area had cellphone service, he said.
The state radio had just flicked back on at that time, Dalgarn added.
He noted in a 3:20 p.m. phone call that the Dave Johnston had a "small" fire with no injuries.
Dave Johnston Didn't Explode
Dalgarn was emphatic that the Dave Johnston fire started after the power outages.
Outages at various locations on the grid can prompt fires at others, Budd said. For her own part, she wanted to dispel rumors that the Dave Johnston plant had exploded. It had only caught fire, she said.
Rocky Mountain Power did not immediately return a voicemail and email request for comment.
The automated responder at the Riverton-based High Plains Power said 3,500 meters in Fremont County were affected.
But the issues were mostly to the northeast of Riverton and spreading into South Dakota, High Plains Power CEO Jon Mayes told Cowboy State Daily in a Thursday phone interview.
His said he believes a generation unit tripped off and caused a cascade of events, though he didn’t know where that may have started.
“I don’t know which generation unit tripped off and caused cascading events, where other lines faulted out and other generation faulted out – which tripped off more things,” he said at about 2:30 p.m. “It’s pretty big right now, we’re trying to fight some voltage issues, and they’re trying to stabilize the grid to be able to bring more load back on.”
The grid needs more load, to reduce the voltage. Maintaining the right voltage and amperage on the grid is “this wild mix” that was “out of whack” as of Thursday afternoon, he said.
Mayes declined to speculate on whether the aurora was a factor, saying he does not know the original cause of the trip.
South Dakota media outlets were reporting outages in the western portion of the state early Thursday afternoon.
"Much of the traffic in Rapid City is currently being controlled by the Rapid City Police Department. Rapid City Public Schools announced that school will remain open until it’s (sic) normal times," KBHB radio reported.
Rapid City government officials have stated that power has been cut for the entirety of the city, with the wider region seeming to have experienced the same blackout conditions, the outlet added.
It added in a later email statement that Black Hills personnel are working to restore power to customers in its service territory in South Dakota and Wyoming, due to the regional electrical outage.
"Our team is now re-energizing the system in segments. As of 2:30 p.m. today, approximately half of our impacted customers have had their power restored," wrote Black Hills. "We will continue to safely restore power to our customers this afternoon and potentially into the evening hours."
Black HIlls' statement says the event happened on the regional transmission grid outside of the Black Hills Energy footprint. The company encouraged customers to:
- Keep refrigerator and freezer doors closed to help preserve food.
- Use flashlights instead of candles to avoid fire hazards.
- Don’t use generators indoors or in enclosed spaces.
- Non-functional traffic signals, treat as a four-way stop.
- Visit its social media channels or Black Hills Energy’s outage map.
The Numbers
The massive power outage has left most of the northeast corner of Wyoming in the dark, along with neighboring areas in Montana and South Dakota.
Nearly 93,000 customers were without power at 2 p.m. Thursday, and by 3:15 that was down to about 70,000.
Rocky Mountain Power customers make up the largest number of those affected by the outage with 32,719 without power, according to poweroutages.com.
Powder River Energy Corp. has 25,348 customers affected, and Montana-Dakota Utilities 9,890.
Those include thousands of people in Natrona, Sheridan, Campbell and Converse counties in central and northeast Wyoming.
A cause of the outage hasn’t been reported.
Thankfully ...
Weston County Emergency Management reported to its Facebook page at about 2:40 p.m. Thursday that the power outage in that area was resolved.
"Emergency Management checked with the Safety Manager at the Refinery to make sure all was good on their front as well," says the statement, adding that local and state authorities were also coordinating with health care providers and among themselves to formulate a plan in case the outage became a long-term incident.
"Thankfully," the agency added, "this didn't last long."
The agency clarified in a 3:20 p.m. post, however, that people on Powder River Energy were still without power, and may remain without it into the night.
This is a developing story and will be updated as more information is available.
