Power outage history
Jefferson County Tennessee
4.3hours
without power for the average customer in a typical year, 2018–2025
42nd most of 73 in Tennessee 35% below the national median
Every day since 2015
Eleven years, one night at a time
Each cell is a day. The brighter it is, the larger the share of Jefferson's customers who were without power at that day's worst moment.
Year by year
Hours in the dark, per customer
2023 was the worst well-recorded year, at 11 hours for the average customer. Hatched years have a thin record and are left out of the averages.
Jefferson, hours without power per customer
The record
The biggest outages since 2015
Ranked by customer-hours lost: customers out multiplied by how long they stayed out. Times are local.
| Began | Storm | Peak out | Share | Lasted | 90% restored | Customer-hours |
|---|---|---|---|---|---|---|
| Aug 7, 2023 | Thunderstorms | 11,865 | 37% | 44 h | 23 h | 161k |
| Sep 27, 2024 | Hurricane Helene | 9,007 | 28% | 2.4 d | 3.5 h | 154k |
| Dec 24, 2020 | Winter storm | 2,698 | 8% | 3.7 d | 19 h | 91k |
| Jul 31, 2020 | Thunderstorms | 5,280 | 16% | 13 h | 2.8 h | 42k |
| Nov 29, 2023 | No storm report | 9,721 | 30% | 6.0 h | 1.0 h | 38k |
| Apr 1, 2023 | No storm report | 8,009 | 25% | 18 h | 5.5 h | 34k |
| Jan 12, 2023 | Tornadoes | 5,494 | 17% | 14 h | 11 h | 32k |
| Jan 3, 2022 | Winter storm | 4,458 | 14% | 13 h | 4.0 h | 21k |
| Dec 23, 2022 | No storm report | 8,634 | 27% | 8.8 h | 12 min | 17k |
| Jul 21, 2022 | Thunderstorms | 3,021 | 9% | 8.5 h | 4.2 h | 12k |
| Dec 24, 2022 | No storm report | 4,252 | 13% | 5.5 h | 2.0 h | 11k |
| Jun 17, 2022 | Thunderstorms | 3,769 | 12% | 6.0 h | 3.8 h | 9.9k |
| May 27, 2017 | No storm report | 881 | 3% | 18 h | – | 9.8k |
| Jul 26, 2021 | No storm report | 4,179 | 13% | 2.8 h | 2.8 h | 8.8k |
| Jul 30, 2024 | Thunderstorms | 2,795 | 9% | 6.2 h | 5.8 h | 8.1k |
| Jan 12, 2024 | No storm report | 1,049 | 3% | 11 h | – | 6.5k |
| Jul 15, 2023 | No storm report | 3,381 | 10% | 2.5 h | 1.5 h | 5.9k |
| May 7, 2023 | Thunderstorms | 2,274 | 7% | 3.2 h | 2.2 h | 5.8k |
| May 27, 2024 | Thunderstorms | 1,285 | 4% | 6.8 h | – | 5.6k |
| Apr 5, 2024 | No storm report | 4,082 | 13% | 1.5 h | 2.0 h | 5.4k |
| Jul 3, 2022 | No storm report | 2,597 | 8% | 3.2 h | 48 min | 5.3k |
| Jun 25, 2022 | Thunderstorms | 1,722 | 5% | 4.2 h | 2.5 h | 4.7k |
| Jun 4, 2020 | No storm report | 1,713 | 5% | 4.8 h | 4.0 h | 4.7k |
| Feb 10, 2024 | No storm report | 2,078 | 6% | 2.5 h | 2.2 h | 4.7k |
| Jun 22, 2019 | Thunderstorms | 1,300 | 4% | 3.5 h | – | 4.5k |
| Aug 22, 2022 | No storm report | 4,357 | 13% | 1.0 h | 5.8 h | 4.4k |
| Jun 22, 2021 | No storm report | 1,717 | 5% | 2.2 h | 1.5 h | 3.9k |
| Aug 14, 2023 | Thunderstorms | 1,895 | 6% | 5.5 h | 2.5 h | 3.8k |
| Jun 26, 2022 | No storm report | 1,163 | 4% | 3.2 h | – | 3.8k |
| Jul 8, 2022 | No storm report | 1,842 | 6% | 2.5 h | 3.8 h | 3.6k |
After the peak
How fast the lights come back
Each line is one major outage, from its peak. The amber line is the typical path.
When it happens
The outage clock
Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.
What was happening
Weather behind the outages
Each outage is matched to NOAA storm reports for Jefferson from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.
- No storm on record 35%
- Thunderstorms 31%
- Tropical storm 17%
- Winter storm 13%
- Tornadoes 3.6%
Who keeps the lights on
Utilities serving Jefferson
As each utility reports to the Energy Information Administration for its whole Tennessee territory, not this county alone. Outage minutes include major storm days.
| Utility | Type | Outage min / yr | Excl. major storms | Outages / yr | Residential ¢/kWh | Customers |
|---|---|---|---|---|---|---|
| Knoxville Utilities Board | Municipal | 274 | 149 | 1.26 | 13.8 | 197k |
| Appalachian Electric Coop | Cooperative | 301 | 215 | 3.20 | 13.6 | 44k |
| City of Newport | Municipal | – | – | – | 15.1 | 20k |
EIA Form 861, latest year each utility reported. Outage minutes are SAIDI, the yearly minutes the average customer goes without power; outages a year are SAIFI.
About these numbers
Notes
Outages come from the EAGLE-I record of utility outage maps collected every 15 minutes by Oak Ridge National Laboratory. Hours without power are customer-hours divided by the county's 32,422 electricity customers. Averages use well-covered years from 2018. Outages shorter than 15 minutes, and utilities that publish no outage map, are not in the record, so these figures understate the total. How every number is made →