The most disaster-prone counties
3,080 counties of 100 sq mi or more, three measures
Which county is most disaster-prone depends on the measure: by FEMA declarations it is Los Angeles County, CA (88), by storm days per square mile Philadelphia County, PA, by FEMA's risk score Los Angeles County, CA. Only 1 county ranks in the top 100 on all three: Pinellas County, FL.
By PlainHazard Editorial · Updated · How this was measured
Counties near the top on every measure
| County | Declarations | Storm days per 1,000 sq mi | Risk score | On |
|---|---|---|---|---|
| Pinellas County, FL | 45 (47th) | 1,852 (94th) | 98.2 (52nd) | 3 of 3 |
| Essex County, NJ | 33 (255th) | 3,085 (15th) | 97.7 (68th) | 2 of 3 |
| Tulsa County, OK | 40 (99th) | 1,322 (196th) | 97.9 (62nd) | 2 of 3 |
| Jefferson Parish, LA | 50 (16th) | 1,060 (311th) | 98.7 (39th) | 2 of 3 |
| Oklahoma County, OK | 52 (12th) | 1,078 (300th) | 97.9 (61st) | 2 of 3 |
| Bergen County, NJ | 32 (302nd) | 2,204 (58th) | 97.8 (64th) | 2 of 3 |
| Duval County, FL | 41 (87th) | 1,087 (291st) | 97.2 (81st) | 2 of 3 |
| Middlesex County, NJ | 30 (380th) | 2,800 (26th) | 97.8 (66th) | 2 of 3 |
| Orange County, CA | 42 (74th) | 888 (470th) | 99.8 (7th) | 2 of 3 |
| Montgomery County, PA | 29 (432nd) | 2,133 (65th) | 96.8 (93rd) | 2 of 3 |
| Philadelphia County, PA | 25 (761st) | 7,005 (1st) | 99.6 (14th) | 2 of 3 |
| Queens County, NY | 25 (761st) | 4,010 (4th) | 99.2 (25th) | 2 of 3 |
| East Baton Rouge Parish, LA | 47 (33rd) | 729 (773rd) | 98.0 (60th) | 2 of 3 |
| Honolulu County, HI | 24 (888th) | 2,929 (22nd) | 98.8 (37th) | 2 of 3 |
| Broward County, FL | 43 (64th) | 638 (1073rd) | 99.5 (17th) | 2 of 3 |
| Milwaukee County, WI | 22 (1170th) | 2,883 (24th) | 98.4 (48th) | 2 of 3 |
| Hillsborough County, FL | 47 (33rd) | 592 (1262nd) | 98.8 (36th) | 2 of 3 |
| Lee County, FL | 45 (47th) | 552 (1406th) | 99.0 (29th) | 2 of 3 |
| Sarasota County, FL | 48 (27th) | 527 (1512th) | 98.2 (54th) | 2 of 3 |
| Manatee County, FL | 50 (16th) | 478 (1737th) | 97.6 (72nd) | 2 of 3 |
| Brevard County, FL | 45 (47th) | 477 (1741st) | 98.4 (47th) | 2 of 3 |
| Miami-Dade County, FL | 43 (64th) | 418 (2018th) | 99.6 (13th) | 2 of 3 |
| Palm Beach County, FL | 41 (87th) | 415 (2034th) | 99.2 (24th) | 2 of 3 |
| Harris County, TX | 41 (87th) | 391 (2160th) | 99.9 (3rd) | 2 of 3 |
| Mobile County, AL | 40 (99th) | 394 (2150th) | 98.0 (58th) | 2 of 3 |
| San Diego County, CA | 51 (15th) | 313 (2445th) | 99.7 (10th) | 2 of 3 |
| Ventura County, CA | 53 (9th) | 229 (2697th) | 99.4 (19th) | 2 of 3 |
| Collier County, FL | 54 (5th) | 201 (2759th) | 98.9 (33rd) | 2 of 3 |
| Kern County, CA | 40 (99th) | 225 (2705th) | 98.9 (34th) | 2 of 3 |
| Riverside County, CA | 66 (2nd) | 172 (2844th) | 99.9 (4th) | 2 of 3 |
Source: FEMA OpenFEMA; NOAA NCEI Storm Events Database; FEMA National Risk Index. FEMA's National Risk Index map.
The top ten on each measure
FEMA declarations since 1953
Storm days per 1,000 sq mi since 1996
- Philadelphia County, PA 7,005
- Carson City (city), NV 5,141
- Delaware County, PA 4,853
- Queens County, NY 4,010
- Camden County, NJ 3,903
- Mercer County, NJ 3,729
- Union County, NJ 3,707
- Greene County, VA 3,636
- Pulaski County, IL 3,433
- Alexander County, IL 3,420
FEMA National Risk Index score
- Los Angeles County, CA 100.0
- Cook County, IL 100.0
- Harris County, TX 99.9
- Riverside County, CA 99.9
- Maricopa County, AZ 99.9
- San Bernardino County, CA 99.8
- Orange County, CA 99.8
- Alameda County, CA 99.8
- Santa Clara County, CA 99.7
- San Diego County, CA 99.7
Source: FEMA OpenFEMA; NOAA NCEI Storm Events Database; FEMA National Risk Index. Search the record at NCEI.
How this was measured
Three measures, each ranked across the 3,080 counties of at least 100 square miles: FEMA declarations naming the county since 1953 (every type, counted once per disaster number); days with a NOAA storm record per 1,000 square miles since 1996 (a day with a zone record counts on every county the zone covers); and FEMA's National Risk Index score. A county counts as near the top when it ranks 100 or better.
Sources
FEMA OpenFEMA Disaster Declarations Summaries (v2), through 2026-10-02; NOAA NCEI Storm Events Database, 1996 to 2026-06-30; FEMA National Risk Index (December 2025).
Limits
Declarations follow requests and federal decisions as well as storms; storm counts follow reporting; the risk score is a model. Agreement between the three is the stronger signal, which is why it leads this page. Counties under 100 square miles are left out because per-area rates swing on small areas.