Power outage history
Missoula County Montana
7.7hours
without power for the average customer in a typical year, 2018–2025
12th most of 35 in Montana 1.2× 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 Missoula's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2024 was the worst well-recorded year, at 39 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Missoula, 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 24, 2024 | Heat | 55,225 | 96% | 4.7 d | 2.7 d | 1.9M |
| Dec 17, 2025 | Windstorm | 8,400 | 15% | 3.5 d | 3.1 d | 243k |
| Aug 23, 2024 | Thunderstorms | 4,181 | 7% | 47 h | 45 h | 94k |
| Feb 1, 2020 | Windstorm | 3,424 | 6% | 19 h | 15 h | 31k |
| Oct 16, 2025 | No storm report | 2,859 | 5% | 7.8 h | – | 22k |
| Nov 15, 2021 | Windstorm | 3,684 | 6% | 12 h | 16 h | 22k |
| Aug 1, 2021 | No storm report | 6,378 | 11% | 4.2 h | 11 h | 21k |
| Jun 19, 2025 | No storm report | 2,717 | 5% | 5.5 h | – | 14k |
| Aug 15, 2024 | Windstorm | 1,477 | 3% | 12 h | – | 14k |
| Mar 30, 2020 | No storm report | 2,070 | 4% | 16 h | – | 13k |
| Oct 13, 2020 | Windstorm | 2,013 | 4% | 5.8 h | – | 11k |
| Nov 25, 2023 | No storm report | 3,172 | 6% | 4.5 h | 4.5 h | 11k |
| Oct 4, 2024 | Windstorm | 2,109 | 4% | 7.5 h | – | 11k |
| Mar 21, 2023 | No storm report | 5,397 | 9% | 1.8 h | 3.0 h | 9.4k |
| Dec 5, 2025 | Winter storm | 3,560 | 6% | 2.5 h | 2.0 h | 8.8k |
| Oct 22, 2024 | No storm report | 2,090 | 4% | 4.8 h | – | 8.7k |
| May 9, 2023 | Flooding | 7,478 | 13% | 1.5 h | 6.0 h | 8.6k |
| Nov 10, 2022 | No storm report | 3,665 | 6% | 2.2 h | 3.0 h | 8.2k |
| Dec 11, 2022 | No storm report | 2,663 | 5% | 3.2 h | – | 8.2k |
| Dec 12, 2022 | No storm report | 2,649 | 5% | 3.0 h | – | 7.9k |
| Jan 13, 2024 | No storm report | 1,046 | 2% | 9.2 h | – | 7.5k |
| Aug 18, 2024 | Thunderstorms | 1,839 | 3% | 6.2 h | – | 7.4k |
| Dec 20, 2023 | No storm report | 6,344 | 11% | 1.2 h | 1.0 h | 7.1k |
| Nov 8, 2024 | No storm report | 3,991 | 7% | 2.5 h | 1.2 h | 7.0k |
| Oct 23, 2024 | No storm report | 4,625 | 8% | 1.5 h | 48 min | 6.9k |
| Oct 5, 2024 | No storm report | 1,394 | 2% | 5.5 h | – | 6.4k |
| Jun 18, 2022 | Thunderstorms | 1,453 | 3% | 4.0 h | – | 5.8k |
| Jul 1, 2021 | Thunderstorms | 1,911 | 3% | 5.0 h | – | 5.7k |
| May 3, 2025 | No storm report | 2,047 | 4% | 2.8 h | – | 5.6k |
| May 4, 2023 | Flooding | 1,270 | 2% | 4.2 h | – | 5.4k |
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 Missoula from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Heat 69%
- Windstorm 13%
- No storm on record 12%
- Thunderstorms 4.3%
- Winter storm 1.0%
- Flooding 0.7%
Who keeps the lights on
Utilities serving Missoula
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 |
| Ravalli County Elec Coop, Inc | MT | 189 | 143 | 2.02 | 10.0 | 141k |
| USBIA-Mission Valley Power | Federal | – | – | – | 9.4 | 16k |
| Missoula Electric Coop, Inc | Cooperative | 1,332 | 363 | 2.40 | 10.9 | 15k |
| Bonneville 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
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 57,348 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 →