County annual report · FIPS 46037
2021 Day County, SD Power Outage Report
In 2021, customers in Day County, SD went without power for an average of 2.9 hours, a total of 12K customer-hours (South Dakota average 3.4 hours). That ranks 31st worst of 61 South Dakota counties and 1881st of 2,974 nationally.
Compared with SD, the US and 2020
Coverage line is EAGLE-I's share of South Dakota customers tracked each year.
Biggest outages in Day County, 2021
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | February 27, 2021 06:00 | February 27, 2021 12:15 | 6h 15m | 2,014 | 3,333 |
| 2 | December 7, 2021 15:15 | December 7, 2021 20:45 | 5h 30m | 582 | 3,201 |
| 3 | April 28, 2021 21:15 | April 28, 2021 23:30 | 2h 15m | 581 | 1,307 |
| 4 | April 7, 2021 18:00 | April 7, 2021 18:30 | 30m | 209 | 105 |
| 5 | April 7, 2021 08:45 | April 7, 2021 10:45 | 2h | 139 | 161 |
| 6 | August 11, 2021 16:15 | August 11, 2021 18:00 | 1h 45m | 131 | 229 |
| 7 | September 3, 2021 12:15 | September 7, 2021 21:30 | 4d 9h | 61 | 1,236 |
| 8 | August 19, 2021 20:00 | August 19, 2021 21:30 | 1h 30m | 58 | 41 |
| 9 | October 5, 2021 16:15 | October 5, 2021 18:45 | 2h 30m | 48 | 73 |
| 10 | August 6, 2021 15:15 | August 6, 2021 17:15 | 2h | 45 | 57 |
Outage episodes by size in 2021: 6 reached 100+ customers, 1 reached 1,000+ customers, 0 reached 10,000+ customers.
Utility reliability filed with the EIA
SAIDI (average outage time per customer) and SAIFI (average interruptions per customer) that utilities serving Day County reported on EIA Form 861 for 2021, or their most recent earlier filing. Utility-wide figures, not county-specific.
| Utility | EIA year | SAIDI | SAIFI | SAIDI excl. major events | SAIFI excl. major events |
|---|---|---|---|---|---|
| Otter Tail Power Co | 2021 | 86 min | 1.13 | 74 min | 1.09 |
| NorthWestern Energy - (SD) | 2021 | 1.5 hrs | 0.95 | 81 min | 0.83 |
| Northern Electric Coop, Inc | 2021 | 2.0 hrs | 1.20 | 1.9 hrs | 1.18 |
| WAPA-- Western Area Power Administration | - | - | - | - | - |
| Montana-Dakota Utilities Co | - | - | - | - | - |
| Codington-Clark Elec Coop, Inc | - | - | - | - | - |
| Lake Region Electric Assn, Inc - (SD) | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 79% of South Dakota's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 4,051 customers (ORNL modeled county customer count), including major storm days. It is comparable across counties but is not the SAIDI a utility files.
- An outage event is a continuous stretch with customers out; counts at 100, 1,000 and 10,000+ use its peak.
- Years loaded: 2015–2025. Day County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Day County, SD annual power outage report, 2021, data as of Oct 3, 2026 02:41 UTC, sources: DOE EAGLE-I (https://eagle-i.doe.gov/); EAGLE-I modeled customer counts (MCC) (https://figshare.com/); EIA Form 861 (utility reliability) (https://www.eia.gov/electricity/data/eia861/). https://massoutage.com/reports/2021/south-dakota/day-county