Power outage history
Carbon County Montana
4.9hours
without power for the average customer in a typical year, 2018–2025
23rd most of 35 in Montana 26% 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 Carbon's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2021 was the worst well-recorded year, at 8.1 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Carbon, 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 |
|---|---|---|---|---|---|---|
| Jun 13, 2022 | Flooding | 2,575 | 40% | 35 h | 11 h | 31k |
| Mar 25, 2023 | Winter storm | 1,639 | 25% | 38 h | 8.8 h | 20k |
| Nov 15, 2021 | Windstorm | 1,329 | 20% | 26 h | 13 h | 14k |
| Sep 3, 2024 | Thunderstorms | 3,383 | 52% | 5.5 h | 2.2 h | 11k |
| Mar 29, 2021 | Windstorm | 499 | 8% | 14 h | 7.2 h | 4.9k |
| Nov 8, 2020 | Winter storm | 948 | 15% | 8.5 h | 3.0 h | 4.7k |
| May 20, 2021 | No storm report | 790 | 12% | 5.5 h | 11 h | 4.3k |
| Dec 17, 2025 | No storm report | 1,580 | 24% | 7.8 h | 12 min | 4.1k |
| Sep 22, 2023 | No storm report | 2,789 | 43% | 2.8 h | 14 h | 4.0k |
| Jun 3, 2021 | No storm report | 984 | 15% | 3.8 h | 1.2 h | 3.6k |
| Jan 28, 2023 | Winter storm | 438 | 7% | 8.0 h | 7.2 h | 3.5k |
| Jun 14, 2024 | Thunderstorms | 1,648 | 25% | 4.2 h | 11 h | 3.5k |
| Jan 14, 2021 | Windstorm | 333 | 5% | 25 h | 1.2 h | 3.2k |
| Jan 13, 2025 | Winter storm | 460 | 7% | 7.0 h | 6.0 h | 2.9k |
| Jun 16, 2020 | No storm report | 1,012 | 16% | 4.8 h | 1.0 h | 2.8k |
| Jun 11, 2025 | Thunderstorms | 451 | 7% | 5.8 h | 12 h | 2.6k |
| Jun 18, 2021 | Wildfire | 1,291 | 20% | 1.8 h | 1.0 h | 2.3k |
| Sep 11, 2023 | No storm report | 981 | 15% | 2.2 h | 2.2 h | 2.2k |
| Jun 26, 2023 | No storm report | 1,900 | 29% | 2.0 h | 1.0 h | 2.1k |
| Nov 25, 2023 | No storm report | 964 | 15% | 2.0 h | 2.0 h | 1.9k |
| Feb 6, 2020 | Winter storm | 996 | 15% | 2.0 h | 48 min | 1.9k |
| Apr 17, 2023 | No storm report | 1,368 | 21% | 1.8 h | 1.0 h | 1.8k |
| Aug 23, 2025 | No storm report | 1,142 | 18% | 1.5 h | 1.5 h | 1.7k |
| Nov 13, 2024 | No storm report | 964 | 15% | 1.8 h | 1.8 h | 1.7k |
| Jun 9, 2025 | No storm report | 451 | 7% | 3.5 h | 3.5 h | 1.6k |
| Feb 9, 2019 | No storm report | 524 | 8% | 9.8 h | 9.8 h | 1.5k |
| May 26, 2021 | No storm report | 536 | 8% | 3.8 h | 2.8 h | 1.5k |
| Aug 2, 2023 | No storm report | 446 | 7% | 3.2 h | 30 min | 1.4k |
| May 16, 2023 | No storm report | 1,133 | 17% | 1.2 h | 1.2 h | 1.4k |
| Apr 23, 2022 | Winter storm | 440 | 7% | 3.0 h | 3.0 h | 1.3k |
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 Carbon from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- No storm on record 41%
- Winter storm 20%
- Flooding 15%
- Windstorm 13%
- Thunderstorms 8.5%
- Wildfire 1.9%
Who keeps the lights on
Utilities serving Carbon
As each utility reports to the Energy Information Administration for its whole Montana territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| NorthWestern Energy LLC | Investor Owned | 125 | 117 | 1.10 | 14.4 | 334k |
| Flathead Electric Coop Inc | Cooperative | 886 | 174 | 2.29 | 10.0 | 64k |
| Beartooth Electric Coop, Inc | MT | – | – | – | 13.1 | 51k |
| Yellowstone Valley Elec Co-op | Cooperative | – | – | – | 14.2 | 21k |
| Big Horn Rural Electric Co | WY | – | – | – | 17.1 | 258 |
| WAPA-- Western Area Power Administration | Federal | – | – | – | – | – |
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
- Park 5.3 h
- Carbon (this county) 4.9 h
- Big Horn, WY 3.0 h
- Yellowstone 2.4 h
- Stillwater 2.0 h
- Park, WY 1.5 h
- Big Horn 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 6,512 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 →