County annual report · FIPS 30111
2023 Yellowstone County, MT Power Outage Report
In 2023, customers in Yellowstone County, MT went without power for an average of 1.4 hours, a total of 105K customer-hours (Montana average 1.8 hours). That ranks 35th worst of 50 Montana counties and 2543rd of 2,977 nationally.
Compared with MT, the US and 2022
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Yellowstone County, 2023
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | September 22, 2023 23:45 | September 23, 2023 11:00 | 11h 15m | 3,149 | 11K |
| 2 | July 24, 2023 19:15 | July 25, 2023 07:15 | 12h | 2,128 | 9,009 |
| 3 | May 22, 2023 03:00 | May 22, 2023 10:15 | 7h 15m | 2,035 | 6,117 |
| 4 | April 10, 2023 16:15 | April 10, 2023 22:15 | 6h | 1,887 | 2,676 |
| 5 | May 27, 2023 14:45 | May 28, 2023 01:45 | 11h | 1,676 | 702 |
| 6 | August 13, 2023 14:30 | August 13, 2023 17:30 | 3h | 1,556 | 2,734 |
| 7 | January 21, 2023 20:45 | January 22, 2023 04:00 | 7h 15m | 1,551 | 6,927 |
| 8 | December 23, 2023 17:45 | December 23, 2023 22:30 | 4h 45m | 1,413 | 2,835 |
| 9 | October 3, 2023 04:30 | October 3, 2023 16:45 | 12h 15m | 1,372 | 3,017 |
| 10 | August 6, 2023 17:15 | August 7, 2023 01:30 | 8h 15m | 1,341 | 1,761 |
Outage episodes by size in 2023: 63 reached 100+ customers, 14 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 2023, 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) | 2023 | 1.7 hrs | 0.93 | 1.7 hrs | 0.93 |
| 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 2023; 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, 2023, 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/2023/montana/yellowstone-county