Clarke CountyPower Outage History
2015–2025 · Iowa
Top 20% most reliable nationally — infrequent, short outages.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Jun 28, 2018 | 5 hrs | 1,254 (29%) | Thunderstorm Wind |
| Oct 25, 2024 | 3 hrs | 1,248 (29%) | Hail |
| May 17, 2015 | 12 hrs | 1,131 (26%) | Thunderstorm Wind |
| Feb 2, 2016 | <1 hr | 1,065 (25%) | Unnamed event |
| Jan 11, 2021 | <1 hr | 907 (21%) | Unnamed event |
Over the 11 years from 2015 to 2025, Clarke County recorded 330 distinct power outage events, averaging 2.0 hours per event.
The single worst outage on record in Clarke County started June 28, 2018 (Thunderstorm Wind), lasting 5 hours and leaving up to 1,254 customers without power (29% of the county) at its peak.
August has historically been the worst month for outages in Clarke County, with 55 events recorded during that month across the dataset.
Based on this history, Clarke County earns a Reliability Grade of A, placing it in the 80th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Clarke County's outage profile
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Outage-prep kit
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Similar counties in Iowa
Counties with the closest reliability grade and national percentile to Clarke County.
| County | Grade | National percentile |
|---|---|---|
| Cerro Gordo County | A | 80th |
| Clayton County | A | 80th |
| Hamilton County | B | 80th |
| Decatur County | B | 79th |
| Madison County | A | 81st |
Most reliable counties in Iowa
The top 3 counties in Iowa by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Clay County | A | 97th |
| Emmet County | A | 95th |
| Bremer County | A | 94th |
Least reliable counties in Iowa
The bottom 3 counties in Iowa by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Marshall County | F | 6th |
| Tama County | F | 12th |
| Jasper County | F | 14th |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
FAQ
How often does power go out in Clarke County?
Between 2015 and 2025, Clarke County recorded 330 outage events, averaging 2.0 hours each.
What is Clarke County's reliability grade?
Clarke County has a Reliability Grade of A, in the 80th national percentile.
What was the worst power outage in Clarke County?
The worst outage on record started June 28, 2018 (Thunderstorm Wind), lasting 5 hours and affecting up to 1,254 customers.