Power outage history
Corson County South Dakota
2.5hours
without power for the average customer in a typical year, 2018–2025
61% 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 Corson's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2024 was the worst well-recorded year, at 2.8 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Corson, 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 |
|---|---|---|---|---|---|---|
| Jul 13, 2024 | No storm report | 224 | 11% | 10 h | 2.2 h | 1.6k |
| Apr 3, 2022 | No storm report | 141 | 7% | 6.5 h | 4.2 h | 856 |
| Jun 12, 2024 | No storm report | 135 | 7% | 5.5 h | 3.8 h | 724 |
| Nov 27, 2024 | No storm report | 281 | 14% | 2.5 h | 2.5 h | 702 |
| Jun 20, 2025 | Thunderstorms | 111 | 6% | 7.5 h | 7.5 h | 656 |
| Sep 24, 2018 | No storm report | 142 | 7% | 4.0 h | 2.5 h | 552 |
| Aug 6, 2020 | No storm report | 131 | 7% | 4.0 h | 4.0 h | 524 |
| Jul 27, 2025 | Windstorm | 141 | 7% | 5.0 h | 14 h | 476 |
| Nov 12, 2024 | No storm report | 209 | 11% | 2.2 h | 2.0 h | 431 |
| Mar 5, 2025 | No storm report | 138 | 7% | 3.0 h | 3.0 h | 414 |
| Apr 23, 2022 | No storm report | 141 | 7% | 2.8 h | 11 h | 376 |
| Aug 14, 2020 | Thunderstorms | 139 | 7% | 2.2 h | 1.0 h | 306 |
| Aug 6, 2024 | No storm report | 162 | 8% | 1.8 h | 1.2 h | 274 |
| Dec 10, 2024 | No storm report | 83 | 4% | 3.8 h | – | 228 |
| Sep 21, 2024 | No storm report | 207 | 10% | 1.2 h | 1.0 h | 220 |
| Jul 9, 2025 | Thunderstorms | 57 | 3% | 3.2 h | – | 183 |
| Oct 13, 2021 | No storm report | 140 | 7% | 1.2 h | 48 min | 173 |
| Jul 15, 2024 | No storm report | 146 | 7% | 1.5 h | 1.5 h | 158 |
| Sep 17, 2024 | No storm report | 74 | 4% | 2.0 h | – | 148 |
| Dec 2, 2025 | No storm report | 63 | 3% | 2.2 h | – | 142 |
| Oct 21, 2024 | No storm report | 55 | 3% | 2.5 h | – | 138 |
| Jun 7, 2022 | No storm report | 132 | 7% | 1.0 h | 1.0 h | 129 |
| Aug 8, 2025 | Thunderstorms | 62 | 3% | 2.0 h | – | 124 |
| Aug 21, 2025 | No storm report | 201 | 10% | 1.2 h | 1.2 h | 122 |
| May 3, 2025 | No storm report | 74 | 4% | 1.5 h | – | 111 |
| Aug 4, 2025 | No storm report | 108 | 5% | 1.0 h | 7.2 h | 108 |
| May 19, 2025 | No storm report | 69 | 3% | 1.5 h | – | 104 |
| Jul 22, 2025 | No storm report | 51 | 3% | 2.0 h | – | 102 |
| Jul 15, 2025 | No storm report | 62 | 3% | 1.8 h | – | 78 |
| Sep 14, 2024 | No storm report | 49 | 2% | 1.5 h | – | 74 |
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 Corson from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- No storm on record 82%
- Thunderstorms 13%
- Windstorm 5.0%
Who keeps the lights on
Utilities serving Corson
As each utility reports to the Energy Information Administration for its whole South Dakota territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Moreau-Grand Electric Coop Inc | SD | – | – | – | 13.2 | 61k |
| Grand Electric Coop, Inc | SD | – | – | – | 11.7 | 52k |
| Montana-Dakota Utilities Co | Investor Owned | 212 | 206 | 2.62 | 13.0 | 6.3k |
| City of McLaughlin | SD | – | – | – | – | 3.1k |
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 1,975 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 →