County annual report · FIPS 30003
2021 Big Horn County, MT Power Outage Report
In 2021, customers in Big Horn County, MT went without power for an average of 0.5 hours, a total of 3,100 customer-hours (Montana average 5.0 hours). That ranks 49th worst of 51 Montana counties and 2827th 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 Big Horn 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 | June 15, 2021 20:00 | June 15, 2021 22:30 | 2h 30m | 105 | 253 |
| 2 | July 28, 2021 10:15 | July 29, 2021 10:45 | 1d | 97 | 801 |
| 3 | January 14, 2021 21:15 | January 14, 2021 22:45 | 1h 30m | 82 | 123 |
| 4 | August 6, 2021 15:15 | August 6, 2021 15:30 | 15m | 82 | 21 |
| 5 | August 6, 2021 16:15 | August 6, 2021 21:00 | 4h 45m | 82 | 369 |
| 6 | February 5, 2021 18:30 | February 5, 2021 23:00 | 4h 30m | 60 | 227 |
| 7 | August 9, 2021 02:00 | August 9, 2021 07:45 | 5h 45m | 49 | 223 |
| 8 | February 24, 2021 20:00 | February 24, 2021 22:00 | 2h | 40 | 80 |
| 9 | March 20, 2021 18:45 | March 20, 2021 20:45 | 2h | 40 | 60 |
| 10 | August 11, 2021 11:00 | August 11, 2021 17:45 | 6h 45m | 37 | 58 |
Outage episodes by size in 2021: 1 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 Big Horn 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 |
| Powder River Energy Corp | 2021 | 5.4 hrs | 2.15 | 3.9 hrs | 1.91 |
| Big Horn Rural Electric Co | 2018 | 4.0 hrs | 1.80 | - | - |
| Mid-Yellowstone Elec Coop, Inc | 2018 | 4.5 hrs | 3.82 | 4.5 hrs | 3.82 |
| WAPA-- Western Area Power Administration | - | - | - | - | - |
| Tongue River Electric Coop Inc | - | - | - | - | - |
| Yellowstone Valley Elec Co-op | - | - | - | - | - |
| Big Horn County Elec 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 ÷ 6,865 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. Big Horn County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Big Horn 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/big-horn-county