County annual report · FIPS 30043
2020 Jefferson County, MT Power Outage Report
In 2020, customers in Jefferson County, MT went without power for an average of 3.6 hours, a total of 19K customer-hours (Montana average 5.6 hours). That ranks 33rd worst of 50 Montana counties and 1708th of 3,019 nationally.
Compared with MT, the US and 2019
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Jefferson County, 2020
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 2, 2020 15:30 | April 2, 2020 18:45 | 3h 15m | 557 | 707 |
| 2 | June 13, 2020 18:00 | June 14, 2020 15:45 | 21h 45m | 352 | 2,023 |
| 3 | September 23, 2020 17:00 | September 23, 2020 22:30 | 5h 30m | 334 | 680 |
| 4 | January 1, 2020 14:30 | January 1, 2020 23:00 | 8h 30m | 332 | 1,742 |
| 5 | October 13, 2020 14:15 | October 13, 2020 17:15 | 3h | 255 | 468 |
| 6 | July 21, 2020 15:00 | July 21, 2020 22:15 | 7h 15m | 247 | 1,044 |
| 7 | October 15, 2020 15:15 | October 15, 2020 21:15 | 6h | 211 | 393 |
| 8 | August 12, 2020 19:45 | August 13, 2020 00:45 | 5h | 191 | 480 |
| 9 | November 29, 2020 15:00 | November 29, 2020 18:30 | 3h 30m | 191 | 456 |
| 10 | July 31, 2020 04:30 | July 31, 2020 06:30 | 2h | 166 | 302 |
Outage episodes by size in 2020: 15 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 Jefferson County reported on EIA Form 861 for 2020, 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) | 2020 | 2.8 hrs | 1.13 | 2.0 hrs | 1.02 |
| Bonneville Power Administration | - | - | - | - | - |
| NorthWestern Energy | - | - | - | - | - |
| Vigilante 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 2020; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 5,322 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. Jefferson County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Jefferson County, MT annual power outage report, 2020, 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/2020/montana/jefferson-county