County annual report · FIPS 30039
2023 Granite County, MT Power Outage Report
In 2023, customers in Granite County, MT went without power for an average of 5.9 hours, a total of 14K customer-hours (Montana average 1.8 hours). That ranks 8th worst of 50 Montana counties and 1309th of 2,977 nationally.
Compared with MT, the US and 2022
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Granite County, 2023
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | May 3, 2023 01:45 | May 3, 2023 05:30 | 3h 45m | 1,425 | 1,436 |
| 2 | February 1, 2023 04:15 | February 1, 2023 09:00 | 4h 45m | 933 | 3,392 |
| 3 | May 3, 2023 14:30 | May 3, 2023 18:15 | 3h 45m | 439 | 777 |
| 4 | January 27, 2023 09:30 | January 27, 2023 13:30 | 4h | 436 | 1,133 |
| 5 | May 5, 2023 05:45 | May 5, 2023 11:30 | 5h 45m | 388 | 877 |
| 6 | June 23, 2023 22:30 | June 24, 2023 00:30 | 2h | 182 | 212 |
| 7 | September 7, 2023 07:30 | September 7, 2023 12:15 | 4h 45m | 166 | 256 |
| 8 | November 14, 2023 16:15 | November 14, 2023 20:45 | 4h 30m | 164 | 541 |
| 9 | December 3, 2023 15:30 | December 3, 2023 20:15 | 4h 45m | 164 | 700 |
| 10 | December 27, 2023 21:15 | December 28, 2023 00:15 | 3h | 164 | 178 |
Outage episodes by size in 2023: 11 reached 100+ customers, 1 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 Granite County reported on EIA Form 861 for 2023, 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) | 2023 | 1.7 hrs | 0.93 | 1.7 hrs | 0.93 |
| Missoula Electric Coop, Inc | 2023 | 2.8 hrs | 1.19 | 2.8 hrs | 1.19 |
| Bonneville Power Administration | - | - | - | - | - |
| NorthWestern Energy | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about n/a of Montana's customers in 2023; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 2,293 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. Granite County has data for 2019–2025.
Cite this report
MassOutage (massoutage.com), Granite County, MT annual power outage report, 2023, 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/2023/montana/granite-county