Worst Power Outages in US History (2014-2025)
The 50 largest single-county power outage events recorded in our dataset (2014-2025), ranked by an approximate customer-hours figure -- duration multiplied by peak customers affected. Sourced from ORNL EAGLE-I (CC BY 4.0). This is a historical record, not a live outage tracker.
| Rank | County | Date | Cause | Duration | Customers affected | Approx. customer-hours |
|---|---|---|---|---|---|---|
| 1 | Los Angeles County, California | Jan 8, 2025 | High Wind | 261 hrs | 1,717,886 (45%) | 447.9M |
| 2 | Harris County, Texas | Jul 8, 2024 | Unnamed event | 258 hrs | 1,660,703 (91%) | 428.5M |
| 3 | Lee County, Florida | Sep 28, 2022 | Hurricane Ian | 502 hrs | 456,573 (68%) | 229.1M |
| 4 | Pinellas County, Florida | Sep 27, 2024 | Unnamed event | 484 hrs | 449,310 (79%) | 217.4M |
| 5 | Wayne County, Michigan | Feb 22, 2023 | Ice Storm | 367 hrs | 311,048 (40%) | 114.1M |
| 6 | Miami-Dade County, Florida | Sep 11, 2017 | Hurricane Irma | 65 hrs | 1,604,860 (89%) | 104.3M |
| 7 | Pinellas County, Florida | Sep 10, 2017 | Hurricane Irma | 229 hrs | 417,553 (73%) | 95.5M |
| 8 | King County, Washington | Nov 19, 2024 | Unnamed event | 178 hrs | 518,386 (53%) | 92M |
| 9 | Greenville County, South Carolina | Sep 27, 2024 | Thunderstorm Wind | 333 hrs | 270,050 (89%) | 89.8M |
| 10 | Calcasieu Parish, Louisiana | Aug 26, 2020 | Unnamed event | 845 hrs | 103,022 (69%) | 87.1M |
| 11 | Orange County, Florida | Sep 10, 2017 | Hurricane Irma | 247 hrs | 331,670 (50%) | 81.8M |
| 12 | Broward County, Florida | Sep 11, 2017 | Hurricane Irma | 65 hrs | 1,258,160 (90%) | 81.8M |
| 13 | Dallas County, Texas | May 28, 2024 | Hail | 211 hrs | 386,856 (34%) | 81.4M |
| 14 | Volusia County, Florida | Sep 10, 2017 | Hurricane Irma | 239 hrs | 318,854 (85%) | 76.1M |
| 15 | Collier County, Florida | Sep 28, 2022 | Tropical Storm Ian | 348 hrs | 212,911 (48%) | 74M |
| 16 | Palm Beach County, Florida | Sep 11, 2017 | Hurricane Irma | 65 hrs | 1,018,980 (91%) | 66.2M |
| 17 | Caguas Municipio, Puerto Rico | Sep 17, 2022 | Unnamed event | 259 hrs | 243,802 (97%) | 63.2M |
| 18 | San Juan Municipio, Puerto Rico | Aug 11, 2024 | Unnamed event | 362 hrs | 174,374 (44%) | 63.1M |
| 19 | Montgomery County, Texas | Jul 8, 2024 | Unnamed event | 255 hrs | 246,212 (70%) | 62.8M |
| 20 | East Baton Rouge Parish, Louisiana | Aug 30, 2021 | Tropical Storm Ida | 405 hrs | 153,064 (70%) | 62M |
| 21 | Spartanburg County, South Carolina | Sep 27, 2024 | Tropical Storm | 336 hrs | 183,816 (72%) | 61.7M |
| 22 | Allegheny County, Pennsylvania | Apr 29, 2025 | Thunderstorm Wind | 218 hrs | 270,977 (41%) | 58.9M |
| 23 | Caguas Municipio, Puerto Rico | Aug 13, 2024 | Tropical Storm Warning | 332 hrs | 175,127 (70%) | 58.1M |
| 24 | Manatee County, Florida | Sep 10, 2017 | Hurricane Irma | 247 hrs | 225,195 (85%) | 55.7M |
| 25 | Mayagüez Municipio, Puerto Rico | Sep 17, 2022 | Unnamed event | 250 hrs | 219,197 (100%) | 54.9M |
| 26 | Bay County, Florida | Oct 10, 2018 | Hurricane Michael | 533 hrs | 100,592 (80%) | 53.6M |
| 27 | Oakland County, Michigan | Feb 22, 2023 | Ice Storm | 370 hrs | 142,457 (22%) | 52.7M |
| 28 | Miami-Dade County, Florida | Sep 8, 2017 | Hurricane Irma | 59 hrs | 898,340 (50%) | 52.6M |
| 29 | Ponce Municipio, Puerto Rico | Sep 17, 2022 | Hurricane Fiona | 242 hrs | 210,593 (99%) | 51M |
| 30 | Arecibo Municipio, Puerto Rico | Sep 17, 2022 | Unnamed event | 258 hrs | 191,803 (100%) | 49.5M |
| 31 | Seminole County, Florida | Sep 10, 2017 | Hurricane Irma | 243 hrs | 198,450 (80%) | 48.2M |
| 32 | Volusia County, Florida | Sep 28, 2022 | Hurricane Ian | 210 hrs | 224,435 (60%) | 47.1M |
| 33 | Lafourche Parish, Louisiana | Sep 7, 2021 | Unnamed event | 1036 hrs | 43,658 (84%) | 45.2M |
| 34 | Suffolk County, New York | Aug 4, 2020 | Tropical Storm Isaias | 228 hrs | 197,669 (30%) | 45M |
| 35 | Brazoria County, Texas | Jul 8, 2024 | Unnamed event | 258 hrs | 164,845 (46%) | 42.6M |
| 36 | Shelby County, Tennessee | Feb 3, 2022 | Ice Storm | 305 hrs | 137,794 (33%) | 42M |
| 37 | Galveston County, Texas | Jul 8, 2024 | Unnamed event | 253 hrs | 164,920 (79%) | 41.7M |
| 38 | Sacramento County, California | Jan 8, 2023 | Drought | 137 hrs | 294,707 (45%) | 40.2M |
| 39 | Marion County, Florida | Sep 10, 2017 | Unnamed event | 227 hrs | 177,207 (77%) | 40.2M |
| 40 | Polk County, Florida | Oct 9, 2024 | Hurricane Milton | 191 hrs | 209,976 (58%) | 40.2M |
| 41 | Jefferson Parish, Louisiana | Aug 30, 2021 | Tropical Storm Ida | 195 hrs | 204,888 (89%) | 40M |
| 42 | Tangipahoa Parish, Louisiana | Aug 29, 2021 | Tropical Storm Ida | 577 hrs | 68,621 (94%) | 39.6M |
| 43 | Manatee County, Florida | Oct 9, 2024 | Hurricane Milton | 179 hrs | 220,455 (83%) | 39.5M |
| 44 | Fairfield County, Connecticut | Aug 4, 2020 | Tropical Storm Isaias | 204 hrs | 190,956 (61%) | 39M |
| 45 | Broward County, Florida | Sep 8, 2017 | Hurricane Irma | 54 hrs | 709,360 (51%) | 38.5M |
| 46 | Bayamón Municipio, Puerto Rico | Sep 16, 2022 | Hurricane Earl | 265 hrs | 145,204 (67%) | 38.4M |
| 47 | Richmond County, Georgia | Sep 27, 2024 | Tropical Storm Helene | 397 hrs | 96,050 (82%) | 38.1M |
| 48 | St. Tammany Parish, Louisiana | Aug 29, 2021 | Tropical Storm Ida | 292 hrs | 130,114 (79%) | 38M |
| 49 | Cuyahoga County, Ohio | Aug 6, 2024 | Tornado | 169 hrs | 223,470 (37%) | 37.8M |
| 50 | Shelby County, Tennessee | Jun 25, 2023 | Excessive Heat | 305 hrs | 120,822 (29%) | 36.8M |
"Unnamed event" means our automated matching found no corresponding storm in NOAA's own records for that county and date -- not a claim that no storm occurred. See methodology below.
The top 5, in detail
#1 Los Angeles County, California — January 8, 2025: High Wind left up to 1,717,886 customers (45% of the county) without power for 261 hours.
#2 Harris County, Texas — July 8, 2024: an outage left up to 1,660,703 customers (91% of the county) without power for 258 hours.
#3 Lee County, Florida — September 28, 2022: Hurricane Ian left up to 456,573 customers (68% of the county) without power for 502 hours.
#4 Pinellas County, Florida — September 27, 2024: an outage left up to 449,310 customers (79% of the county) without power for 484 hours.
#5 Wayne County, Michigan — February 22, 2023: Ice Storm left up to 311,048 customers (40% of the county) without power for 367 hours.
FAQ
What was the worst power outage in US history?
By our ranking metric (duration × peak customers affected), the top-scoring single event in our dataset is Los Angeles County, California — January 8, 2025: High Wind left up to 1,717,886 customers (45% of the county) without power for 261 hours. See the full top-50 ranking above, and the methodology note below on how "worst" is defined here.
How is this ranked?
We rank each county's worst recorded outage event by an approximate customer-hours figure: the event's duration in hours multiplied by its peak number of customers without power. This is an explicit approximation, not a precise integral over the whole event (see methodology) -- it favors outages that were both large and long, so a very brief outage that still affected a large share of a county's customers can rank lower here than its local impact would suggest. Events from a county-year flagged as data-quality-suspect are excluded from this ranking.
Does this include recent or ongoing outages?
No. This page ranks historical events already fully recorded in our dataset (2014-2025), refreshed annually -- it is not a live outage tracker. For current outage status, check your utility's own outage map.
Methodology & caveats
Ranked by duration (hours) × peak customers affected, an approximation of customer-hours for a single event -- county_worst_events doesn't store a true integral per event the way our yearly/county rollups do. This approximation favors outages that were both large andlong: a brief outage that still affected a large share of a county's customers (for example, one detected in a single 15-minute reading) will rank lower here than its local impact alone would suggest. Percent-of-county affected is shown as its own column for that reason -- don't read rank position alone as a complete severity measure.
Storm names come from NOAA's Storm Events Database narratives. Not every event has a matching named storm in NOAA's own records, even when a real named storm was involved -- that reflects a gap in automated matching, not a claim that no storm occurred.
Events from any county-year flagged as data-quality-suspect are excluded from this ranking (see methodology). Data covers 2014 through the last full year (currently 2025) and refreshes annually.
Live somewhere storm-prone?
State-specific prep checklists for states appearing in the top 50: Texas, Florida, Michigan, Louisiana, New York. See our best generators & power stations for outages roundups for backup power options.