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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 994 events. The data includes river floods, flash floods, coastal flooding, and hurricane-related flooding.

RankCountyTotal EventsRiver FloodsFlash Floods
1San Bernardino County994159835
2San Diego County497234256
3Kern County455321134
4Riverside County428133295
5Fresno County34431232
6Sonoma County28824444
7Inyo County25324229
8Tulare County23821820
9Los Angeles County22514210
10Alameda County17514827
11Santa Clara County16614224
12Monterey County14911532
13Sacramento County1471389
14Orange County1387858
15Merced County1331276
16Imperial County11816102
17Marin County1149519
18Mariposa County105987
19San Francisco County98935
20Humboldt County97942
21Butte County96879
22Ventura County961482
23San Mateo County956332
24Santa Cruz County955836
25Santa Barbara County801169
26Madera County76715
27Shasta County726012
28Contra Costa County705812
29Mendocino County66651
30Tehama County62548
31Placer County554312
32El Dorado County50473
33Napa County473314
34Yolo County44431
35San Joaquin County43394
36Kings County40346
37San Luis Obispo County401129
38Siskiyou County301020
39Nevada County28244
40Tuolumne County241113
41San Benito County23176
42Solano County23212
43Mono County231310
44Calaveras County23185
45Lake County23212
46Glenn County21210
47Colusa County19181
48Plumas County17143
49Stanislaus County17170
50Sutter County14140
51Amador County13103
52Modoc County1284
53Yuba County12102
54Lassen County1192
55Del Norte County1192
56Trinity County743
57Sierra County330
58Alpine County220

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

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