County annual report · FIPS 30091
2021 Sheridan County, MT Power Outage Report
In 2021, customers in Sheridan County, MT went without power for an average of 2.7 hours, a total of 4,837 customer-hours (Montana average 5.0 hours). That ranks 31st worst of 51 Montana counties and 1941st of 2,974 nationally.
Compared with MT, the US and 2020
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Sheridan 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 | January 14, 2021 05:15 | January 14, 2021 06:00 | 45m | 991 | 256 |
| 2 | January 14, 2021 07:00 | January 14, 2021 09:45 | 2h 45m | 390 | 591 |
| 3 | June 24, 2021 00:00 | June 24, 2021 06:30 | 6h 30m | 261 | 427 |
| 4 | April 9, 2021 03:30 | April 9, 2021 08:45 | 5h 15m | 204 | 1,064 |
| 5 | June 11, 2021 03:30 | June 11, 2021 08:45 | 5h 15m | 174 | 461 |
| 6 | June 19, 2021 12:00 | June 19, 2021 13:00 | 1h | 153 | 79 |
| 7 | July 17, 2021 13:15 | July 17, 2021 15:00 | 1h 45m | 40 | 26 |
| 8 | April 1, 2021 16:00 | April 1, 2021 17:15 | 1h 15m | 30 | 38 |
| 9 | June 10, 2021 21:30 | June 10, 2021 23:15 | 1h 45m | 27 | 47 |
| 10 | July 8, 2021 21:45 | July 8, 2021 22:30 | 45m | 27 | 16 |
Outage episodes by size in 2021: 6 reached 100+ customers, 0 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 Sheridan 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 |
|---|---|---|---|---|---|
| Montana-Dakota Utilities Co | - | - | - | - | - |
| Sheridan Electric Coop, Inc | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 76% of Montana's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 1,766 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. Sheridan County has data for 2017–2025.
Cite this report
MassOutage (massoutage.com), Sheridan County, MT 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/). https://massoutage.com/reports/2021/montana/sheridan-county