County annual report · FIPS 30049
2021 Lewis and Clark County, MT Power Outage Report
In 2021, customers in Lewis and Clark County, MT went without power for an average of 7.2 hours, a total of 236K customer-hours (Montana average 5.0 hours). That ranks 22nd worst of 51 Montana counties and 1016th 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 Lewis and Clark 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 3, 2021 23:45 | June 4, 2021 22:15 | 22h 30m | 27,788 | 72K |
| 2 | July 19, 2021 12:45 | July 19, 2021 15:00 | 2h 15m | 5,593 | 11K |
| 3 | April 6, 2021 05:45 | April 6, 2021 13:30 | 7h 45m | 5,516 | 14K |
| 4 | August 26, 2021 17:15 | August 27, 2021 02:00 | 8h 45m | 4,527 | 7,262 |
| 5 | January 13, 2021 16:00 | January 17, 2021 07:15 | 3d 15h | 3,470 | 40K |
| 6 | May 8, 2021 01:00 | May 8, 2021 12:00 | 11h | 3,408 | 7,401 |
| 7 | February 22, 2021 16:15 | February 22, 2021 22:45 | 6h 30m | 3,023 | 6,509 |
| 8 | July 17, 2021 02:45 | July 17, 2021 05:00 | 2h 15m | 2,686 | 6,044 |
| 9 | April 5, 2021 18:45 | April 6, 2021 00:00 | 5h 15m | 2,408 | 5,215 |
| 10 | August 4, 2021 13:15 | August 6, 2021 15:30 | 2d 2h | 1,516 | 3,963 |
Outage episodes by size in 2021: 60 reached 100+ customers, 14 reached 1,000+ customers, 1 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 Lewis and Clark 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 | - | - | - | - | - |
| Vigilante Electric Coop, Inc | - | - | - | - | - |
| Sun River 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 ÷ 32,887 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. Lewis and Clark County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Lewis and Clark 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/lewis-and-clark-county