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Most Flood-Prone Counties in California

Based on NOAA Storm Events Database records from 1996 to 2025, these are the California counties with the most recorded flood events. San Bernardino County tops the list with 1,000 events. The data includes river floods, flash floods, coastal flooding, and hurricane-related flooding.

RankCountyTotal EventsRiver FloodsFlash Floods
1San Bernardino County1,000162835
2San Diego County538247256
3Kern County455321134
4Riverside County435135295
5Fresno County34431232
6Sonoma County31224444
7Inyo County25324229
8Tulare County23821820
9Los Angeles County22514210
10Alameda County17814827
11Santa Clara County17014224
12Sacramento County1671589
13Orange County1527858
14Monterey County15111532
15Marin County1389519
16Merced County1331276
17Imperial County11816102
18San Francisco County112985
19Butte County106979
20Mariposa County105987
21Humboldt County102942
22Santa Cruz County1025836
23San Mateo County1016332
24Ventura County961482
25Shasta County877512
26Placer County806812
27Santa Barbara County801169
28Madera County76715
29El Dorado County75723
30Contra Costa County735812
31Tehama County72648
32Mendocino County67651
33Napa County583314
34Yolo County58571
35San Joaquin County57534
36Nevada County46424
37Amador County45423
38Solano County43412
39Tuolumne County422913
40Calaveras County41365
41Kings County40346
42San Luis Obispo County401129
43Siskiyou County371720
44Sutter County35350
45Glenn County30300
46Yuba County29272
47Colusa County28271
48Stanislaus County25250
49Mono County241410
50San Benito County23176
51Lake County23212
52Plumas County19163
53Modoc County14104
54Lassen County13112
55Del Norte County1392
56Trinity County743
57Sierra County550
58Alpine County440

Source: NOAA Storm Events Database (1996–2025).

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