County annual report · FIPS 30111
2025 Yellowstone County, MT Power Outage Report
In 2025, customers in Yellowstone County, MT went without power for an average of 2.8 hours, a total of 217K customer-hours (Montana average 6.8 hours). That ranks 36th worst of 51 Montana counties and 2136th 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 Yellowstone 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 | April 17, 2025 07:00 | April 18, 2025 06:30 | 23h 30m | 7,083 | 44K |
| 2 | December 17, 2025 19:15 | December 21, 2025 02:15 | 3d 7h | 5,735 | 45K |
| 3 | October 25, 2025 21:30 | October 26, 2025 03:15 | 5h 45m | 2,775 | 3,143 |
| 4 | October 5, 2025 14:00 | October 5, 2025 22:00 | 8h | 2,515 | 6,912 |
| 5 | April 2, 2025 14:00 | April 2, 2025 15:45 | 1h 45m | 2,491 | 3,543 |
| 6 | February 3, 2025 12:15 | February 3, 2025 13:15 | 1h | 1,876 | 473 |
| 7 | August 7, 2025 21:00 | August 8, 2025 08:15 | 11h 15m | 1,863 | 6,730 |
| 8 | June 26, 2025 14:15 | June 27, 2025 01:00 | 10h 45m | 1,841 | 4,641 |
| 9 | June 16, 2025 12:15 | June 17, 2025 13:00 | 1d | 1,795 | 5,745 |
| 10 | December 9, 2025 16:15 | December 10, 2025 02:15 | 10h | 1,729 | 3,882 |
Outage episodes by size in 2025: 74 reached 100+ customers, 22 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 Yellowstone 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 |
| Mid-Yellowstone Elec Coop, Inc | 2018 | 4.5 hrs | 3.82 | 4.5 hrs | 3.82 |
| WAPA-- Western Area Power Administration | - | - | - | - | - |
| NorthWestern Energy | - | - | - | - | - |
| Fergus Electric Coop, Inc | - | - | - | - | - |
| Yellowstone Valley Elec Co-op | - | - | - | - | - |
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 ÷ 77,606 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. Yellowstone County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Yellowstone 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/yellowstone-county