County annual report · FIPS 30013
2021 Cascade County, MT Power Outage Report
In 2021, customers in Cascade County, MT went without power for an average of 5.0 hours, a total of 194K customer-hours (Montana average 5.0 hours). That ranks 26th worst of 51 Montana counties and 1338th 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 Cascade 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 | April 12, 2021 00:45 | April 12, 2021 06:15 | 5h 30m | 6,002 | 17K |
| 2 | April 4, 2021 09:00 | April 5, 2021 18:45 | 1d 9h | 3,815 | 14K |
| 3 | May 20, 2021 13:30 | May 21, 2021 01:15 | 11h 45m | 3,044 | 11K |
| 4 | January 13, 2021 10:45 | January 19, 2021 01:30 | 5d 14h | 2,733 | 37K |
| 5 | April 18, 2021 22:00 | April 19, 2021 04:15 | 6h 15m | 2,498 | 8,082 |
| 6 | March 22, 2021 15:00 | March 23, 2021 01:15 | 10h 15m | 2,253 | 3,486 |
| 7 | January 21, 2021 16:45 | January 22, 2021 02:15 | 9h 30m | 2,246 | 2,921 |
| 8 | November 16, 2021 03:30 | November 16, 2021 23:30 | 20h | 2,104 | 7,044 |
| 9 | April 8, 2021 14:45 | April 8, 2021 23:45 | 9h | 2,013 | 2,077 |
| 10 | July 28, 2021 21:00 | July 29, 2021 02:30 | 5h 30m | 1,974 | 5,444 |
Outage episodes by size in 2021: 65 reached 100+ customers, 18 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 Cascade 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 | - | - | - | - | - |
| Fergus 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 ÷ 39,166 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. Cascade County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Cascade 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/cascade-county