County annual report · FIPS 30097
2021 Sweet Grass County, MT Power Outage Report
In 2021, customers in Sweet Grass County, MT went without power for an average of 8.1 hours, a total of 16K customer-hours (Montana average 5.0 hours). That ranks 18th worst of 51 Montana counties and 929th 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 Sweet Grass 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 | October 26, 2021 10:15 | October 26, 2021 18:15 | 8h | 1,314 | 6,247 |
| 2 | March 9, 2021 20:00 | March 9, 2021 22:00 | 2h | 608 | 912 |
| 3 | January 12, 2021 20:30 | January 15, 2021 07:15 | 2d 10h | 331 | 3,316 |
| 4 | July 28, 2021 19:45 | July 29, 2021 02:15 | 6h 30m | 288 | 1,237 |
| 5 | September 1, 2021 21:45 | September 1, 2021 23:30 | 1h 45m | 225 | 338 |
| 6 | March 18, 2021 21:30 | March 18, 2021 22:45 | 1h 15m | 126 | 130 |
| 7 | June 25, 2021 02:15 | June 25, 2021 07:00 | 4h 45m | 118 | 87 |
| 8 | March 15, 2021 18:30 | March 15, 2021 21:00 | 2h 30m | 111 | 221 |
| 9 | December 1, 2021 06:45 | December 1, 2021 14:15 | 7h 30m | 93 | 268 |
| 10 | August 4, 2021 01:15 | August 4, 2021 05:15 | 4h | 86 | 318 |
Outage episodes by size in 2021: 8 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 Sweet Grass 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 |
|---|---|---|---|---|---|
| NorthWestern Energy LLC - (MT) | 2021 | 2.5 hrs | 1.37 | 2.1 hrs | 1.18 |
| Fergus Electric Coop, Inc | - | - | - | - | - |
| Beartooth Electric Coop, Inc | - | - | - | - | - |
| Park 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 ÷ 1,993 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. Sweet Grass County has data for 2020–2025.
Cite this report
MassOutage (massoutage.com), Sweet Grass 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/); EIA Form 861 (utility reliability) (https://www.eia.gov/electricity/data/eia861/). https://massoutage.com/reports/2021/montana/sweet-grass-county