Power outage history
Sheridan County Wyoming
2.5hours
without power for the average customer in a typical year, 2018–2025
10th most of 20 in Wyoming 62% below the national median
Every day since 2015
Eleven years, one night at a time
Each cell is a day. The brighter it is, the larger the share of Sheridan's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2025 was the worst well-recorded year, at 4.5 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Sheridan, hours without power per customer
The record
The biggest outages since 2015
Ranked by customer-hours lost: customers out multiplied by how long they stayed out. Times are local.
| Began | Storm | Peak out | Share | Lasted | 90% restored | Customer-hours |
|---|---|---|---|---|---|---|
| Nov 13, 2025 | No storm report | 12,017 | 68% | 6.0 h | 4.0 h | 48k |
| Oct 12, 2021 | Winter storm | 2,784 | 16% | 22 h | 15 h | 27k |
| Feb 15, 2023 | No storm report | 3,907 | 22% | 6.2 h | 4.5 h | 9.7k |
| Aug 18, 2021 | No storm report | 1,346 | 8% | 8.0 h | 5.2 h | 8.4k |
| Jul 18, 2022 | No storm report | 1,094 | 6% | 7.8 h | 7.8 h | 8.3k |
| Oct 5, 2022 | No storm report | 2,109 | 12% | 7.0 h | 7.0 h | 7.6k |
| Sep 11, 2022 | No storm report | 4,930 | 28% | 2.2 h | 12 min | 7.5k |
| Jan 25, 2022 | No storm report | 568 | 3% | 12 h | – | 6.2k |
| Jul 29, 2020 | No storm report | 1,008 | 6% | 6.2 h | 6.5 h | 6.2k |
| Sep 11, 2024 | No storm report | 985 | 6% | 6.5 h | 7.2 h | 6.2k |
| Apr 22, 2022 | Winter storm | 3,262 | 19% | 5.2 h | 4.2 h | 5.7k |
| Dec 19, 2025 | Windstorm | 1,045 | 6% | 8.8 h | 19 h | 5.6k |
| Jul 13, 2024 | No storm report | 338 | 2% | 16 h | – | 4.8k |
| Aug 1, 2023 | No storm report | 809 | 5% | 5.8 h | – | 4.6k |
| May 31, 2025 | No storm report | 1,653 | 9% | 5.0 h | 1.5 h | 4.5k |
| Jan 5, 2021 | No storm report | 2,052 | 12% | 5.5 h | 5.2 h | 4.3k |
| Dec 19, 2025 | No storm report | 203 | 1% | 19 h | – | 3.7k |
| Apr 10, 2021 | No storm report | 1,219 | 7% | 3.2 h | 1.0 h | 3.5k |
| Oct 4, 2017 | No storm report | 534 | 3% | 7.8 h | – | 3.5k |
| Jun 30, 2021 | No storm report | 523 | 3% | 7.5 h | – | 3.4k |
| Apr 25, 2017 | No storm report | 808 | 5% | 8.0 h | – | 3.2k |
| Jun 13, 2022 | Thunderstorms | 574 | 3% | 5.2 h | – | 3.0k |
| Oct 1, 2020 | No storm report | 483 | 3% | 5.8 h | – | 2.8k |
| Jun 13, 2022 | No storm report | 572 | 3% | 4.5 h | – | 2.6k |
| Sep 27, 2018 | No storm report | 815 | 5% | 8.5 h | – | 2.2k |
| Oct 19, 2023 | No storm report | 542 | 3% | 4.2 h | – | 2.2k |
| Apr 23, 2022 | Winter storm | 815 | 5% | 5.2 h | – | 2.1k |
| Sep 6, 2023 | No storm report | 467 | 3% | 4.2 h | – | 1.9k |
| Aug 9, 2023 | No storm report | 459 | 3% | 4.5 h | – | 1.9k |
| Dec 14, 2021 | No storm report | 399 | 2% | 4.8 h | – | 1.8k |
After the peak
How fast the lights come back
Each line is one major outage, from its peak. The amber line is the typical path.
When it happens
The outage clock
Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.
What was happening
Weather behind the outages
Each outage is matched to NOAA storm reports for Sheridan from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- No storm on record 77%
- Winter storm 17%
- Windstorm 3.2%
- Thunderstorms 2.9%
Who keeps the lights on
Utilities serving Sheridan
As each utility reports to the Energy Information Administration for its whole Wyoming territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Big Horn Rural Electric Co | WY | 208 | – | 1.29 | 14.9 | 31k |
| Powder River Energy Corp | Cooperative | 571 | 271 | 3.50 | 12.2 | 16k |
| Montana-Dakota Utilities Co | Investor Owned | 354 | 134 | 1.80 | 12.0 | 15k |
| Big Horn County Elec Coop, Inc | MT | – | – | – | 11.8 | 3.9k |
EIA Form 861, latest year each utility reported. Outage minutes are SAIDI, the yearly minutes the average customer goes without power; outages a year are SAIFI.
Next door
Neighbouring counties
- Johnson 5.5 h
- Campbell 3.3 h
- Big Horn 3.0 h
- Sheridan (this county) 2.5 h
- Big Horn, MT 0.9 h
About these numbers
Notes
Outages come from the EAGLE-I record of utility outage maps collected every 15 minutes by Oak Ridge National Laboratory. Hours without power are customer-hours divided by the county's 17,618 electricity customers. Averages use well-covered years from 2018. Outages shorter than 15 minutes, and utilities that publish no outage map, are not in the record, so these figures understate the total. How every number is made →