Power outage history
Black Hawk County Iowa
1.5hours
without power for the average customer in a typical year, 2018–2025
91st most of 98 in Iowa 77% 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 Black Hawk'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 2.6 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Black Hawk, 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 |
|---|---|---|---|---|---|---|
| Sep 9, 2019 | Thunderstorms | 14,037 | 24% | 18 h | 6.0 h | 80k |
| Jul 30, 2025 | Thunderstorms | 12,895 | 22% | 16 h | 13 h | 57k |
| May 21, 2024 | Flooding | 7,552 | 13% | 13 h | 12 h | 44k |
| May 17, 2017 | Thunderstorms | 3,319 | 6% | 22 h | 24 h | 31k |
| Mar 6, 2017 | Thunderstorms | 8,304 | 14% | 4.5 h | 2.0 h | 20k |
| Jul 9, 2020 | Thunderstorms | 7,424 | 13% | 6.5 h | 5.2 h | 18k |
| Jul 6, 2022 | No storm report | 3,477 | 6% | 5.2 h | 2.5 h | 18k |
| Sep 22, 2016 | Thunderstorms | 19,627 | 34% | 3.2 h | 12 min | 17k |
| Jul 29, 2025 | Thunderstorms | 5,227 | 9% | 12 h | 5.2 h | 15k |
| May 26, 2016 | Thunderstorms | 3,166 | 6% | 8.8 h | 10 h | 15k |
| Jul 15, 2020 | No storm report | 8,078 | 14% | 3.2 h | 1.0 h | 13k |
| Aug 10, 2020 | No storm report | 2,480 | 4% | 9.2 h | – | 12k |
| Jul 14, 2021 | Thunderstorms | 2,495 | 4% | 7.0 h | – | 9.3k |
| May 16, 2025 | No storm report | 2,754 | 5% | 7.5 h | – | 8.2k |
| Apr 7, 2017 | No storm report | 4,257 | 7% | 1.2 h | 12 min | 5.2k |
| Jun 11, 2025 | Thunderstorms | 1,645 | 3% | 4.0 h | – | 4.3k |
| Nov 22, 2015 | No storm report | 2,173 | 4% | 2.2 h | – | 4.3k |
| Jun 29, 2019 | No storm report | 2,438 | 4% | 1.8 h | – | 4.3k |
| Jul 3, 2025 | No storm report | 1,640 | 3% | 3.5 h | – | 4.2k |
| Apr 3, 2024 | No storm report | 962 | 2% | 4.5 h | – | 4.0k |
| Jul 8, 2017 | No storm report | 3,927 | 7% | 1.0 h | 1.8 h | 3.6k |
| Jun 19, 2024 | Thunderstorms | 2,352 | 4% | 1.5 h | – | 3.5k |
| Jun 11, 2016 | Thunderstorms | 3,718 | 6% | 1.0 h | 30 min | 3.5k |
| Apr 16, 2023 | No storm report | 1,619 | 3% | 2.0 h | – | 3.2k |
| Jul 25, 2018 | No storm report | 4,815 | 8% | 1.5 h | 1.5 h | 3.2k |
| Mar 9, 2019 | No storm report | 1,520 | 3% | 2.2 h | – | 3.1k |
| Jul 28, 2025 | Thunderstorms | 961 | 2% | 3.2 h | – | 3.0k |
| Jun 20, 2025 | No storm report | 2,193 | 4% | 1.5 h | – | 2.9k |
| Nov 20, 2017 | No storm report | 4,644 | 8% | 1.0 h | 10 h | 2.9k |
| Feb 3, 2016 | Winter storm | 846 | 1% | 5.5 h | – | 2.7k |
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 Black Hawk from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- Thunderstorms 47%
- No storm on record 39%
- Flooding 12%
- Winter storm 1.4%
- Ice storm 0.5%
Who keeps the lights on
Utilities serving Black Hawk
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 |
| Grundy County Rural Elec Coop | IA | 62 | 62 | 0.86 | 14.1 | 28k |
| Cedar Falls Utilities | Municipal | 37 | – | 0.54 | 11.6 | 18k |
| La Porte City Utilities | IA | – | – | – | – | 9.3k |
| East-Central Iowa Rural Elec Coop | Cooperative | 67 | 67 | 0.88 | 13.1 | 7.4k |
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 57,533 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 →