Sierra CountyPower Outage History
2018–2025 · California
Bottom 20% least reliable nationally — frequent and/or long outages.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Feb 28, 2023 | 133 hrs | 4,203 (77%) | Winter Storm |
| Mar 5, 2023 | 56 hrs | 3,988 (73%) | Blizzard |
| Mar 2, 2024 | 145 hrs | 2,454 (45%) | Blizzard |
| Mar 15, 2020 | 16 hrs | 1,701 (31%) | Heavy Snow |
| Nov 23, 2024 | 40 hrs | 1,682 (31%) | Heavy Snow |
Over the 8 years from 2018 to 2025, Sierra County recorded 818 distinct power outage events, averaging 7.5 hours per event.
The single worst outage on record in Sierra County started February 28, 2023 (Winter Storm), lasting 133 hours and leaving up to 4,203 customers without power (77% of the county) at its peak.
October has historically been the worst month for outages in Sierra County, with 174 events recorded during that month across the dataset.
Based on this history, Sierra County earns a Reliability Grade of F, placing it in the 0th percentile nationally for grid reliability (higher percentile = more reliable).
Sized for Sierra County's outage profile
See more picks in our Best Dual-Fuel Portable Generators for Power Outages roundup.
Champion Power Equipment 4375-Watt Dual Fuel RV Ready Portable Generator with Free 3-Year Warranty
Outage-prep kit
See our outage-prep guides.
Similar counties in California
Counties with the closest reliability grade and national percentile to Sierra County.
| County | Grade | National percentile |
|---|---|---|
| Plumas County | F | 1st |
| Mariposa County | F | 1st |
| Calaveras County | F | 1st |
| Amador County | F | 1st |
| Tuolumne County | F | 1st |
Most reliable counties in California
The top 3 counties in California by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Stanislaus County | A | 97th |
| Lassen County | A | 96th |
| San Benito County | B | 80th |
Least reliable counties in California
The bottom 3 counties in California by reliability grade and percentile.
| County | Grade | National percentile |
|---|---|---|
| Sierra County | F | 0th |
| Plumas County | F | 1st |
| Mariposa County | F | 1st |
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 Sierra County?
Between 2018 and 2025, Sierra County recorded 818 outage events, averaging 7.5 hours each.
What is Sierra County's reliability grade?
Sierra County has a Reliability Grade of F, in the 0th national percentile.
What was the worst power outage in Sierra County?
The worst outage on record started February 28, 2023 (Winter Storm), lasting 133 hours and affecting up to 4,203 customers.