County annual report · FIPS 30105
2021 Valley County, MT Power Outage Report
In 2021, customers in Valley County, MT went without power for an average of 15.7 hours, a total of 61K customer-hours (Montana average 5.0 hours). That ranks 8th worst of 51 Montana counties and 544th 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 Valley 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 | July 23, 2021 00:30 | July 23, 2021 06:30 | 6h | 3,217 | 8,711 |
| 2 | November 5, 2021 02:45 | November 5, 2021 10:00 | 7h 15m | 3,174 | 21K |
| 3 | March 8, 2021 16:30 | March 8, 2021 18:45 | 2h 15m | 2,890 | 4,004 |
| 4 | March 22, 2021 15:00 | March 22, 2021 16:15 | 1h 15m | 2,730 | 3,017 |
| 5 | August 18, 2021 06:30 | August 18, 2021 10:30 | 4h | 1,299 | 2,562 |
| 6 | January 14, 2021 08:00 | January 16, 2021 00:45 | 1d 16h | 1,256 | 8,664 |
| 7 | June 11, 2021 12:15 | June 11, 2021 23:30 | 11h 15m | 699 | 2,374 |
| 8 | July 8, 2021 21:30 | July 9, 2021 02:45 | 5h 15m | 600 | 2,350 |
| 9 | May 5, 2021 22:30 | May 6, 2021 01:45 | 3h 15m | 466 | 701 |
| 10 | November 13, 2021 19:30 | November 13, 2021 21:30 | 2h | 465 | 929 |
Outage episodes by size in 2021: 16 reached 100+ customers, 6 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 Valley 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 |
| WAPA-- Western Area Power Administration | - | - | - | - | - |
| NorthWestern Energy | - | - | - | - | - |
| NorVal Electric Cooperative, Inc | - | - | - | - | - |
| Big Flat 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 76% of Montana's customers in 2021; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 3,912 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. Valley County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Valley 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/valley-county