County annual report · FIPS 30111
2019 Yellowstone County, MT Power Outage Report
In 2019, customers in Yellowstone County, MT went without power for an average of 0.0 hours, a total of 39 customer-hours (Montana average 0.6 hours). That ranks 34th worst of 38 Montana counties and 2930th of 2,945 nationally.
Compared with MT, the US
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Yellowstone County, 2019
The 4 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | December 24, 2019 05:00 | December 24, 2019 08:00 | 3h | 8 | 24 |
| 2 | December 27, 2019 00:45 | December 27, 2019 02:30 | 1h 45m | 6 | 11 |
| 3 | December 27, 2019 14:45 | December 27, 2019 17:00 | 2h 15m | 1 | 2 |
| 4 | December 29, 2019 21:45 | December 29, 2019 23:30 | 1h 45m | 1 | 2 |
Outage episodes by size in 2019: 0 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 Yellowstone County reported on EIA Form 861 for 2019, 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) | 2018 | 1.7 hrs | 1.08 | 1.7 hrs | 1.08 |
| 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 75% of Montana's customers in 2019; 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, 2019, 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/2019/montana/yellowstone-county