Power outage history
Custer County Montana
0.6hours
without power for the average customer in a typical year, 2018–2025
91% 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 Custer's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2023 was the worst well-recorded year, at 38 min for the average customer. Hatched years have a thin record and are left out of the averages.
Custer, 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 |
|---|---|---|---|---|---|---|
| Jul 13, 2024 | Thunderstorms | 2,045 | 29% | 24 h | 20 h | 31k |
| Dec 3, 2020 | No storm report | 4,487 | 65% | 1.0 h | 1.0 h | 4.5k |
| Aug 20, 2020 | No storm report | 1,689 | 24% | 2.2 h | 2.0 h | 3.2k |
| Jul 11, 2023 | Thunderstorms | 2,691 | 39% | 1.2 h | 1.0 h | 2.7k |
| May 5, 2024 | No storm report | 586 | 8% | 4.5 h | 3.5 h | 2.3k |
| Jun 12, 2017 | Thunderstorms | 878 | 13% | 9.2 h | 4.8 h | 2.3k |
| Aug 11, 2024 | No storm report | 1,375 | 20% | 1.5 h | 1.5 h | 1.8k |
| Sep 12, 2024 | No storm report | 888 | 13% | 4.8 h | 3.2 h | 1.4k |
| Apr 12, 2017 | No storm report | 4,145 | 60% | 48 min | 30 min | 1.4k |
| Oct 23, 2022 | No storm report | 405 | 6% | 3.2 h | 3.2 h | 1.3k |
| Jul 10, 2017 | Thunderstorms | 517 | 7% | 4.0 h | 5.0 h | 1.2k |
| Aug 1, 2022 | No storm report | 345 | 5% | 3.8 h | – | 1.2k |
| Feb 10, 2018 | No storm report | 969 | 14% | 3.2 h | 1.2 h | 1.1k |
| Nov 13, 2021 | No storm report | 676 | 10% | 1.5 h | 1.5 h | 1.0k |
| May 23, 2020 | No storm report | 253 | 4% | 4.5 h | – | 998 |
| Jul 25, 2017 | No storm report | 646 | 9% | 1.5 h | 1.5 h | 969 |
| Apr 24, 2019 | No storm report | 521 | 8% | 2.0 h | 2.0 h | 958 |
| Oct 12, 2021 | Winter storm | 296 | 4% | 6.8 h | – | 948 |
| Jul 7, 2019 | No storm report | 757 | 11% | 1.2 h | 1.2 h | 936 |
| May 20, 2020 | Thunderstorms | 835 | 12% | 1.0 h | 1.0 h | 832 |
| Jul 14, 2019 | Thunderstorms | 534 | 8% | 3.0 h | 1.0 h | 768 |
| Aug 19, 2020 | No storm report | 881 | 13% | 1.2 h | 12 h | 758 |
| Sep 15, 2017 | No storm report | 372 | 5% | 1.5 h | 1.5 h | 558 |
| Oct 1, 2017 | No storm report | 1,092 | 16% | 30 min | 30 min | 546 |
| Jun 18, 2023 | No storm report | 671 | 10% | 48 min | 48 min | 503 |
| Jul 22, 2020 | No storm report | 175 | 3% | 3.0 h | – | 502 |
| Sep 11, 2020 | No storm report | 212 | 3% | 2.2 h | – | 477 |
| Jun 28, 2020 | No storm report | 121 | 2% | 4.8 h | – | 459 |
| Mar 4, 2020 | Windstorm | 873 | 13% | 30 min | 12 min | 434 |
| Nov 30, 2019 | No storm report | 348 | 5% | 1.2 h | 48 min | 432 |
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 Custer from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Thunderstorms 53%
- No storm on record 43%
- Windstorm 1.8%
- Winter storm 1.7%
Who keeps the lights on
Utilities serving Custer
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 |
|---|---|---|---|---|---|---|
| Tongue River Electric Coop Inc | MT | – | – | – | 14.1 | 56k |
| McCone Electric Coop Inc | MT | – | – | – | 13.5 | 49k |
| Montana-Dakota Utilities Co | Investor Owned | 146 | 146 | 1.23 | 12.3 | 20k |
| Southeast Electric Coop, Inc | MT | 443 | 443 | – | – | 19k |
| Mid-Yellowstone Elec Coop, Inc | MT | 207 | 207 | 2.22 | 12.5 | 15k |
| 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
- Rosebud 3.1 h
- Custer (this county) 0.6 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 6,942 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 →