County annual report · FIPS 30043
2025 Jefferson County, MT Power Outage Report
In 2025, customers in Jefferson County, MT went without power for an average of 20.9 hours, a total of 111K customer-hours (Montana average 6.8 hours). That ranks 7th worst of 51 Montana counties and 330th of 3,000 nationally.
Compared with MT, the US and 2024
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Jefferson County, 2025
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | December 17, 2025 16:00 | December 21, 2025 22:00 | 4d 6h | 6,022 | 98K |
| 2 | October 13, 2025 09:15 | October 13, 2025 14:15 | 5h | 1,490 | 3,447 |
| 3 | May 14, 2025 14:15 | May 14, 2025 21:45 | 7h 30m | 1,449 | 776 |
| 4 | August 6, 2025 15:30 | August 6, 2025 21:15 | 5h 45m | 1,107 | 2,217 |
| 5 | August 22, 2025 17:00 | August 22, 2025 20:30 | 3h 30m | 384 | 485 |
| 6 | June 15, 2025 21:15 | June 16, 2025 01:15 | 4h | 242 | 344 |
| 7 | December 9, 2025 18:15 | December 9, 2025 20:00 | 1h 45m | 212 | 371 |
| 8 | October 21, 2025 20:15 | October 21, 2025 22:45 | 2h 30m | 131 | 328 |
| 9 | April 8, 2025 13:45 | April 8, 2025 16:45 | 3h | 107 | 311 |
| 10 | April 21, 2025 17:15 | April 21, 2025 21:00 | 3h 45m | 70 | 263 |
Outage episodes by size in 2025: 9 reached 100+ customers, 4 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 Jefferson County reported on EIA Form 861 for 2025, 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) | 2024 | 3.9 hrs | 1.30 | 2.0 hrs | 0.95 |
| Bonneville Power Administration | - | - | - | - | - |
| NorthWestern Energy | - | - | - | - | - |
| Vigilante 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 n/a of Montana's customers in 2025; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 5,322 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. Jefferson County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Jefferson County, MT annual power outage report, 2025, 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/2025/montana/jefferson-county