County annual report · FIPS 30039
2025 Granite County, MT Power Outage Report
In 2025, customers in Granite County, MT went without power for an average of 5.8 hours, a total of 13K customer-hours (Montana average 6.8 hours). That ranks 27th worst of 51 Montana counties and 1310th of 3,000 nationally.
Compared with MT, the US and 2024
Coverage line is EAGLE-I's share of Montana customers tracked each year.
Biggest outages in Granite County, 2025
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, 2025 13:00 | April 12, 2025 14:00 | 1h | 603 | 155 |
| 2 | May 5, 2025 03:00 | May 5, 2025 04:15 | 1h 15m | 470 | 588 |
| 3 | September 6, 2025 23:15 | September 7, 2025 00:15 | 1h | 402 | 307 |
| 4 | September 29, 2025 17:30 | September 29, 2025 20:45 | 3h 15m | 402 | 1,233 |
| 5 | August 31, 2025 13:00 | August 31, 2025 16:45 | 3h 45m | 343 | 1,193 |
| 6 | December 17, 2025 16:15 | December 19, 2025 02:15 | 1d 10h | 246 | 2,226 |
| 7 | April 5, 2025 14:45 | April 5, 2025 23:15 | 8h 30m | 217 | 968 |
| 8 | January 29, 2025 12:45 | January 29, 2025 18:30 | 5h 45m | 201 | 372 |
| 9 | June 12, 2025 23:00 | June 13, 2025 00:00 | 1h | 196 | 148 |
| 10 | December 5, 2025 06:30 | December 5, 2025 13:30 | 7h | 175 | 866 |
Outage episodes by size in 2025: 13 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 Granite County reported on EIA Form 861 for 2025, 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) | 2024 | 3.9 hrs | 1.30 | 2.0 hrs | 0.95 |
| Missoula Electric Coop, Inc | 2024 | 26.8 hrs | 3.59 | 8.4 hrs | 2.19 |
| 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 2025; 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, 2025, 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/2025/montana/granite-county