Black Hawk County Power Outage History
2015–2025 · Iowa
Top 20% most reliable nationally — infrequent, short outages. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Sep 22, 2016 | 3 hrs | 32,746 (51%) | Thunderstorm Wind |
| May 31, 2018 | 2 hrs | 17,227 (27%) | Unnamed event |
| Sep 9, 2019 | 20 hrs | 14,037 (22%) | Thunderstorm Wind |
| Jul 30, 2025 | 20 hrs | 12,895 (20%) | Thunderstorm Wind |
| Mar 7, 2017 | 7 hrs | 8,304 (13%) | Thunderstorm Wind |
Over the 11 years from 2015 to 2025, Black Hawk County recorded 315 distinct power outage events, averaging 1.9 hours per event.
The single worst outage on record in Black Hawk County started September 22, 2016 (Thunderstorm Wind), lasting 3 hours and leaving up to 32,746 customers without power (51% of the county) at its peak.
July has historically been the worst month for outages in Black Hawk County, with 46 events recorded during that month across the dataset.
Based on this history, Black Hawk County earns a Reliability Grade of A, placing it in the 88th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Black Hawk County's outage profile
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Similar counties in Iowa
Counties with the closest reliability grade and national percentile to Black Hawk County.
| County | Grade | National percentile |
|---|---|---|
| Carroll County | A | 88th |
| Osceola County | A | 88th |
| Plymouth County | A | 88th |
| Marion County | A | 89th |
| Cass County | A | 89th |
FAQ
How often does power go out in Black Hawk County?
Between 2015 and 2025, Black Hawk County recorded 315 outage events, averaging 1.9 hours each.
What is Black Hawk County's reliability grade?
Black Hawk County has a Reliability Grade of A, in the 88th national percentile.
What was the worst power outage in Black Hawk County?
The worst outage on record started September 22, 2016 (Thunderstorm Wind), lasting 3 hours and affecting up to 32,746 customers.