Union CountyPower Outage History
What this grade means
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 |
|---|---|---|---|
| Sep 6, 2016 | 1 hrs | 3,566 (51%) | Unnamed event |
| Jul 23, 2022 | 2 hrs | 2,144 (30%) | Drought |
| Oct 3, 2021 | 1 hrs | 1,843 (26%) | Unnamed event |
| Jul 13, 2024 | 1 hrs | 1,806 (26%) | Flood |
| Jul 11, 2016 | 3 hrs | 1,781 (25%) | Unnamed event |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Union County, South Dakota that day.
Over the 11 years from 2015 to 2025, Union County recorded 190 distinct power outage events, averaging 2.6 hours per event.
The single worst outage on record in Union County started September 6, 2016, lasting 1 hours and leaving up to 3,566 customers without power (51% of the county) at its peak.
July has historically been the worst month for outages in Union County, with 33 events recorded during that month across the dataset.
Based on this history, Union County earns a Reliability Grade of A, placing it in the 86th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in South Dakota
Counties with the closest reliability grade and national percentile to Union County.
| County | Grade | National percentile |
|---|---|---|
| Meade County | A | 86th |
| Butte County | A | 85th |
| Bon Homme County | A | 85th |
| Aurora County | A | 87th |
| Roberts County | A | 83rd |
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 Union County?
Between 2015 and 2025, Union County recorded 190 outage events, averaging 2.6 hours each.
What is Union County's reliability grade?
Union County has a Reliability Grade of A, in the 86th national percentile.
What was the worst power outage in Union County?
The worst outage on record started September 6, 2016, lasting 1 hours and affecting up to 3,566 customers.