Big Horn CountyPower Outage History
2017–2025 · Wyoming
Top 20% most reliable nationally — infrequent, short outages.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Jul 9, 2021 | <1 hr | 2,303 (40%) | Unnamed event |
| Aug 1, 2020 | 3 hrs | 2,279 (40%) | Unnamed event |
| Apr 8, 2021 | 2 hrs | 1,771 (31%) | High Wind |
| Oct 15, 2018 | <1 hr | 1,765 (31%) | Unnamed event |
| Nov 19, 2025 | 1 hrs | 1,675 (29%) | Unnamed event |
Over the 9 years from 2017 to 2025, Big Horn County recorded 161 distinct power outage events, averaging 2.1 hours per event.
The single worst outage on record in Big Horn County started July 9, 2021, lasting less than 1 hour and leaving up to 2,303 customers without power (40% of the county) at its peak.
July has historically been the worst month for outages in Big Horn County, with 25 events recorded during that month across the dataset.
Based on this history, Big Horn County earns a Reliability Grade of A, placing it in the 82nd percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Big Horn County's outage profile
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Outage-prep kit
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Similar counties in Wyoming
Counties with the closest reliability grade and national percentile to Big Horn County.
| County | Grade | National percentile |
|---|---|---|
| Sheridan County | A | 82nd |
| Sweetwater County | A | 81st |
| Campbell County | B | 80th |
| Natrona County | A | 87th |
| Park County | A | 88th |
Most reliable counties in Wyoming
The top 3 counties in Wyoming by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Teton County | A | 97th |
| Fremont County | A | 94th |
| Niobrara County | A | 93rd |
Least reliable counties in Wyoming
The bottom 3 counties in Wyoming by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Crook County | C | 41st |
| Converse County | C | 48th |
| Weston County | B | 64th |
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 Big Horn County?
Between 2017 and 2025, Big Horn County recorded 161 outage events, averaging 2.1 hours each.
What is Big Horn County's reliability grade?
Big Horn County has a Reliability Grade of A, in the 82nd national percentile.
What was the worst power outage in Big Horn County?
The worst outage on record started July 9, 2021, lasting less than 1 hour and affecting up to 2,303 customers.