County annual report · FIPS 30011
2021 Carter County, MT Power Outage Report
In 2021, customers in Carter County, MT went without power for an average of 0.0 hours, a total of 7 customer-hours (Montana average 5.0 hours). That ranks 51st worst of 51 Montana counties and 2954th of 2,974 nationally.
Compared with MT, the US and 2019
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Carter County, 2021
The 2 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 17:00 | April 12, 2021 21:15 | 4h 15m | 1 | 4 |
| 2 | November 4, 2021 15:45 | November 4, 2021 18:15 | 2h 30m | 1 | 3 |
Outage episodes by size in 2021: 0 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 Carter 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 |
|---|---|---|---|---|---|
| Black Hills Power, Inc. | 2021 | 2.6 hrs | 1.17 | 41 min | 0.32 |
| Tongue River Electric Coop Inc | - | - | - | - | - |
| Grand Electric Coop, Inc | - | - | - | - | - |
| Southeast 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 ÷ 508 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. Carter County has data for 2016–2019, 2021–2022, 2024–2025.
Cite this report
MassOutage (massoutage.com), Carter 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/carter-county