Lewis and Clark County Power Outage History
2020–2025 · Montana
Better than average — fewer or shorter outages than most counties. How grades are calculated
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Jun 4, 2021 | 3 hrs | 27,788 (80%) | Unnamed event |
| Jun 3, 2025 | 3 hrs | 12,309 (36%) | Thunderstorm Wind |
| Dec 17, 2025 | 24 hrs | 9,800 (28%) | High Wind |
| Jun 3, 2020 | 2 hrs | 8,404 (24%) | Unnamed event |
| Jul 19, 2021 | 2 hrs | 5,593 (16%) | Unnamed event |
Over the 6 years from 2020 to 2025, Lewis and Clark County recorded 201 distinct power outage events, averaging 3.3 hours per event.
The single worst outage on record in Lewis and Clark County started June 4, 2021, lasting 3 hours and leaving up to 27,788 customers without power (80% of the county) at its peak.
July has historically been the worst month for outages in Lewis and Clark County, with 26 events recorded during that month across the dataset.
Based on this history, Lewis and Clark County earns a Reliability Grade of B, placing it in the 73rd percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Lewis and Clark County's outage profile
See more picks in our Best Small Power Stations (Under 1,000Wh) roundup.
Outage-prep kit
See our outage-prep guides.
Similar counties in Montana
Counties with the closest reliability grade and national percentile to Lewis and Clark County.
| County | Grade | National percentile |
|---|---|---|
| Hill County | B | 72nd |
| Ravalli County | B | 72nd |
| Prairie County | B | 71st |
| Sheridan County | B | 75th |
| Cascade County | B | 69th |
FAQ
How often does power go out in Lewis and Clark County?
Between 2020 and 2025, Lewis and Clark County recorded 201 outage events, averaging 3.3 hours each.
What is Lewis and Clark County's reliability grade?
Lewis and Clark County has a Reliability Grade of B, in the 73rd national percentile.
What was the worst power outage in Lewis and Clark County?
The worst outage on record started June 4, 2021, lasting 3 hours and affecting up to 27,788 customers.