Mellette CountyPower Outage History
2020–2025 · South Dakota
Top 20% most reliable nationally — infrequent, short outages. This county ranks in the most reliable fifth of all US counties in our dataset, based on 12 years of real DOE outage records: outages happen less often here, and when they do occur they tend to be resolved quickly compared to the rest of the country. Baseline outage risk is low, though a severe local storm can still occasionally cause a longer-than-usual outage regardless of the long-term track record.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Mar 30, 2024 | 5 hrs | 533 (64%) | Winter Weather |
| Apr 19, 2024 | 5 hrs | 425 (51%) | Thunderstorm Wind |
| Apr 29, 2025 | <1 hr | 389 (46%) | Unnamed event |
| Nov 26, 2024 | 2 hrs | 49 (6%) | High Wind |
| Sep 14, 2024 | 2 hrs | 37 (4%) | Unnamed event |
Over the 6 years from 2020 to 2025, Mellette County recorded 28 distinct power outage events, averaging 3.9 hours per event.
The single worst outage on record in Mellette County started March 30, 2024 (Winter Weather), lasting 5 hours and leaving up to 533 customers without power (64% of the county) at its peak.
March has historically been the worst month for outages in Mellette County, with 5 events recorded during that month across the dataset.
Based on this history, Mellette County earns a Reliability Grade of A, placing it in the 92nd percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Mellette County's outage profile
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Read our mission →Similar counties in South Dakota
Counties with the closest reliability grade and national percentile to Mellette County.
| County | Grade | National percentile |
|---|---|---|
| Lincoln County | A | 92nd |
| Stanley County | A | 93rd |
| Edmunds County | A | 93rd |
| Campbell County | A | 93rd |
| Walworth County | A | 94th |
Most reliable counties in South Dakota
The top 3 counties in South Dakota by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Clay County | A | 100th |
| Codington County | A | 98th |
| Tripp County | A | 98th |
Least reliable counties in South Dakota
The bottom 3 counties in South Dakota by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Harding County | D | 21st |
| Perkins County | D | 29th |
| Custer County | D | 30th |
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 Mellette County?
Between 2020 and 2025, Mellette County recorded 28 outage events, averaging 3.9 hours each.
What is Mellette County's reliability grade?
Mellette County has a Reliability Grade of A, in the 92nd national percentile.
What was the worst power outage in Mellette County?
The worst outage on record started March 30, 2024 (Winter Weather), lasting 5 hours and affecting up to 533 customers.