Power outage history
Hamilton County Iowa
2.4hours
without power for the average customer in a typical year, 2018–2025
69th most of 98 in Iowa 64% 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 Hamilton's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2020 was the worst well-recorded year, at 6.8 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Hamilton, 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 |
|---|---|---|---|---|---|---|
| Aug 10, 2020 | Thunderstorms | 1,142 | 12% | 3.8 d | 14 h | 39k |
| Dec 15, 2021 | Tornadoes | 1,621 | 18% | 47 h | 8.0 h | 25k |
| Mar 4, 2025 | Winter storm | 599 | 7% | 36 h | 19 h | 13k |
| Dec 10, 2021 | No storm report | 1,317 | 14% | 16 h | 12 h | 8.7k |
| Jan 24, 2020 | No storm report | 1,108 | 12% | 5.0 h | 10 h | 5.5k |
| Apr 13, 2018 | Thunderstorms | 565 | 6% | 8.0 h | 3.0 h | 3.7k |
| May 9, 2017 | No storm report | 1,109 | 12% | 2.8 h | 2.8 h | 3.0k |
| Oct 16, 2019 | No storm report | 663 | 7% | 4.2 h | 4.2 h | 2.8k |
| Jun 17, 2020 | No storm report | 1,098 | 12% | 2.5 h | 2.5 h | 2.7k |
| Jun 3, 2020 | No storm report | 685 | 7% | 3.8 h | 4.2 h | 2.6k |
| Nov 4, 2020 | No storm report | 1,096 | 12% | 2.2 h | 2.2 h | 2.5k |
| Feb 3, 2016 | Winter storm | 1,123 | 12% | 2.0 h | 2.0 h | 2.2k |
| Mar 14, 2023 | No storm report | 822 | 9% | 3.0 h | 2.2 h | 2.0k |
| Mar 19, 2025 | Winter storm | 699 | 8% | 6.8 h | 4.5 h | 1.8k |
| Feb 23, 2019 | Winter storm | 146 | 2% | 12 h | – | 1.7k |
| Aug 15, 2025 | No storm report | 690 | 8% | 2.5 h | 1.8 h | 1.7k |
| Oct 23, 2015 | No storm report | 245 | 3% | 6.2 h | – | 1.5k |
| Oct 17, 2018 | No storm report | 1,084 | 12% | 1.2 h | 1.0 h | 1.1k |
| May 1, 2018 | No storm report | 413 | 4% | 2.8 h | – | 1.1k |
| Apr 2, 2020 | No storm report | 1,431 | 16% | 1.0 h | 48 min | 1.1k |
| Jan 19, 2023 | Winter storm | 159 | 2% | 6.8 h | – | 1.0k |
| Dec 5, 2023 | No storm report | 153 | 2% | 6.8 h | – | 1.0k |
| May 18, 2023 | No storm report | 629 | 7% | 1.5 h | 1.0 h | 943 |
| May 9, 2020 | No storm report | 146 | 2% | 6.5 h | – | 892 |
| Feb 16, 2021 | Winter storm | 647 | 7% | 1.8 h | 1.0 h | 792 |
| Jan 14, 2022 | Winter storm | 202 | 2% | 3.8 h | – | 757 |
| May 24, 2024 | Thunderstorms | 186 | 2% | 5.0 h | – | 756 |
| Sep 16, 2023 | No storm report | 206 | 2% | 4.0 h | – | 756 |
| Aug 18, 2024 | No storm report | 1,077 | 12% | 48 min | 48 min | 754 |
| May 25, 2023 | No storm report | 629 | 7% | 3.0 h | 30 min | 743 |
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 Hamilton from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- No storm on record 36%
- Thunderstorms 32%
- Tornadoes 17%
- Winter storm 14%
Who keeps the lights on
Utilities serving Hamilton
As each utility reports to the Energy Information Administration for its whole Iowa territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| MidAmerican Energy Co | Investor Owned | 205 | 82 | 1.19 | 11.2 | 640k |
| Interstate Power and Light Co | Investor Owned | 89 | 74 | 0.82 | 17.8 | 419k |
| City of Webster City | IA | – | – | – | 12.9 | 32k |
| City of Story City | IA | – | – | – | 12.1 | 17k |
| Midland Power Coop | Cooperative | 488 | 91 | 1.79 | 13.7 | 12k |
| Prairie Energy Coop | Cooperative | 428 | 121 | 3.11 | 14.1 | 3.4k |
| City of Stratford | IA | – | – | – | – | 2.5k |
| City of Ellsworth | IA | – | – | – | – | 1.8k |
| Pleasant Hill Community Line | IA | – | – | – | 9.7 | 1.7k |
| City of Stanhope | IA | – | – | – | – | 1.6k |
| Cass Electric Coop | IA | – | – | – | – | 1.2k |
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.
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 9,205 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 →