Riskiest Counties for Riverine Flood

Ranked by FEMA National Risk Index riverine flood hazard score · code IFLD

Riverine Flood risk reflects rivers and streams overflowing their banks after heavy rain or snowmelt. FEMA's National Risk Index scores each county's riverine flood hazard from its expected annual loss, annualized event frequency, and exposed population. Los Angeles County, California currently leads the nation with a riverine flood score of 100.0 and $2.81B in expected annual loss. California, Texas, Arizona account for much of the highest-rated riverine flood risk in this dataset.

Read the full riverine flood risk guide — how FEMA scores it and how to prepare →

County Rankings

#CountyStateRiverine Flood ScoreRatingAnn. Freq.Ann. Loss
1Los Angeles CountyCA
100.0
Very High 3.96 / yr$2.81B
2Harris CountyTX
100.0
Very High 5.14 / yr$1.12B
3Cook CountyIL
99.9
Very High 5.89 / yr$1.10B
4Maricopa CountyAZ
99.9
Very High 8.46 / yr$1.12B
5Riverside CountyCA
99.9
Very High 7.36 / yr$1.13B
6Orange CountyCA
99.8
Very High 2.89 / yr$820M
7San Bernardino CountyCA
99.8
Very High 12.96 / yr$960M
8Santa Clara CountyCA
99.8
Very High 2.07 / yr$720M
9Alameda CountyCA
99.7
Very High 2.25 / yr$491M
10San Diego CountyCA
99.7
Very High 7.89 / yr$648M
11Miami-Dade CountyFL
99.7
Very High 4.00 / yr$356M
12Bexar CountyTX
99.7
Very High 7.46 / yr$365M
13Dallas CountyTX
99.6
Very High 4.61 / yr$324M
14Clark CountyNV
99.6
Very High 7.25 / yr$362M
15Philadelphia CountyPA
99.6
Very High 5.82 / yr$266M
16King CountyWA
99.5
Very High 0.29 / yr$417M
17Contra Costa CountyCA
99.5
Very High 1.18 / yr$412M
18Pima CountyAZ
99.5
Very High 12.82 / yr$347M
19Broward CountyFL
99.4
Very High 2.46 / yr$289M
20Kings CountyNY
99.4
Very High 1.96 / yr$181M
21Wayne CountyMI
99.4
Very High 3.14 / yr$237M
22Ventura CountyCA
99.3
Very High 1.93 / yr$313M
23Queens CountyNY
99.3
Very High 3.29 / yr$185M
24Honolulu CountyHI
99.3
Very High 5.93 / yr$330M
25Sonoma CountyCA
99.2
High 2.54 / yr$280M

Showing the top 25 seeded counties for riverine flood risk.

Riverine Flood Risk by State

DelawareNew JerseyCaliforniaConnecticutArizonaMassachusettsFloridaHawaiiSouth CarolinaWashingtonNew HampshireNew YorkPennsylvaniaNorth CarolinaOregonLouisianaAlabamaMarylandWisconsinNew MexicoMaineRhode IslandOklahomaArkansasOhioIllinoisTennesseeMississippiMissouriMichiganWest VirginiaTexasNevadaIndianaKentuckyMinnesotaColoradoIowaGeorgiaIdahoWyomingVermontUtahAlaskaVirginiaMontanaKansasSouth DakotaNebraskaNorth Dakota