Lewis and Clark CountyPower Outage History
What this grade means
Better than average — fewer or shorter outages than most counties. This county's outage history is better than the national median: recorded outages are less frequent and/or shorter in duration than a typical US county experienced over the same 12-year period. It isn't in the top tier nationally, but its track record points to lower-than-average outage risk.
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 |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Lewis and Clark County, Montana that day.
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).
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 |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
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.