FEMA NRI v1.20Released December 2025Methodology

California Disaster Risk

Natural disaster risk data for all 58 counties.

FEMA release

December 2025

Mean county NRI score

88.7

Counties with Data

of 58 total

County risk atlas

California hazard exposure by county

FEMA NRI v1.20 scores on a 0–100 relative scale. Toggle the composite and five selected hazard categories out of FEMA's 18. Flood is the higher of Coastal Flooding and Inland Flooding NRI scores.

Counties

58/58

Mean county NRI score

88.7

Risk layers

Highest Risk Counties

Los Angeles County

Very High

NRI score 100.0

Riverside County

Very High

NRI score 99.9

San Bernardino County

Very High

NRI score 99.8

Orange County

Very High

NRI score 99.8

Alameda County

Very High

NRI score 99.8

Lowest Risk Counties

Alpine County

Very Low

NRI score 10.6

Sierra County

Very Low

NRI score 31.5

Modoc County

Very Low

NRI score 39.7

Mono County

Relatively Low

NRI score 46.5

Lassen County

Relatively Low

NRI score 73.1

All California Counties

County	NRI score	FEMA Rating	Flood	Wildfire	Tornado	Earthquake
Los Angeles County	100.0	Very High	100.0	99.9	97.7	100.0
Riverside County	99.9	Very High	99.9	100.0	86.7	99.8
San Bernardino County	99.8	Very High	99.8	99.9	78.8	99.8
Orange County	99.8	Very High	99.8	99.8	83.7	99.9
Alameda County	99.8	Very High	99.7	97.7	65.8	100.0
Santa Clara County	99.7	Very High	99.8	97.4	55.8	99.9
San Diego County	99.7	Very High	99.7	100.0	64.4	99.7
San Francisco County	99.5	Very High	98.6	28.7	34.9	99.8
Contra Costa County	99.5	Very High	99.5	97.6	49.9	99.7
Ventura County	99.4	Relatively High	99.3	99.8	42.4	99.7
Fresno County	99.3	Relatively High	98.7	98.4	57.1	99.2
San Mateo County	99.2	Relatively High	98.4	92.0	30.6	99.7
Sonoma County	99.1	Relatively High	99.2	98.2	15.4	99.5
Santa Barbara County	99.0	Relatively High	98.6	99.2	5.4	99.4
Kern County	98.9	Relatively High	98.5	99.7	19.8	99.4
Monterey County	98.7	Relatively High	97.3	98.7	28.7	99.4
San Joaquin County	98.6	Relatively High	97.7	92.0	49.0	99.3
Sacramento County	98.1	Relatively High	99.0	95.9	65.0	98.9
Santa Cruz County	97.8	Relatively High	96.2	97.3	18.7	99.3
Tulare County	97.0	Relatively High	98.1	98.0	30.3	97.9
Solano County	97.0	Relatively High	97.4	94.5	34.1	99.0
Stanislaus County	96.9	Relatively High	96.0	95.0	27.8	98.5
Merced County	96.9	Relatively High	94.7	92.2	26.2	98.5
Humboldt County	96.8	Relatively High	94.2	95.5	7.9	99.0
Imperial County	96.5	Relatively High	94.1	76.0	11.4	99.2
Madera County	96.4	Relatively High	94.0	99.4	19.3	96.9
Marin County	96.4	Relatively High	97.2	94.6	18.6	98.7
San Luis Obispo County	95.9	Relatively High	96.7	98.3	6.1	97.9
Napa County	95.3	Relatively High	95.8	96.0	18.3	98.4
Del Norte County	94.4	Relatively High	77.8	85.7	3.3	94.2
Mendocino County	94.3	Relatively High	95.1	97.8	10.5	98.3
Butte County	93.9	Relatively Moderate	93.2	98.5	28.2	97.5
Shasta County	93.4	Relatively Moderate	94.8	99.5	15.4	96.5
Placer County	93.1	Relatively Moderate	95.8	98.7	23.3	95.2
Lake County	93.0	Relatively Moderate	94.1	99.1	10.9	97.0
Kings County	92.4	Relatively Moderate	87.7	77.1	16.4	97.0
El Dorado County	91.4	Relatively Moderate	91.7	99.7	13.7	91.6
Yolo County	91.4	Relatively Moderate	89.6	87.0	22.4	97.4
Nevada County	89.9	Relatively Moderate	89.9	99.4	17.9	92.1
Siskiyou County	89.0	Relatively Moderate	90.9	98.6	1.9	88.2
Tehama County	88.9	Relatively Moderate	90.0	98.5	12.9	94.3
Calaveras County	86.6	Relatively Moderate	77.6	99.5	8.0	76.7
Mariposa County	86.4	Relatively Moderate	70.8	99.0	6.4	67.5
Plumas County	86.4	Relatively Moderate	87.9	98.6	9.8	92.2
San Benito County	85.2	Relatively Moderate	69.4	95.4	10.2	97.3
Tuolumne County	85.2	Relatively Moderate	81.0	99.3	7.9	71.0
Sutter County	83.7	Relatively Moderate	71.4	77.1	14.9	94.1
Colusa County	81.1	Relatively Moderate	37.9	89.1	9.3	90.8
Yuba County	80.9	Relatively Low	83.8	96.8	14.9	90.1
Trinity County	79.5	Relatively Low	79.0	98.5	4.7	85.0
Inyo County	79.3	Relatively Low	61.6	83.7	2.9	94.3
Amador County	79.2	Relatively Low	70.0	98.1	6.0	64.5
Glenn County	74.4	Relatively Low	42.3	91.8	8.8	92.5
Lassen County	73.1	Relatively Low	74.4	97.5	3.2	89.7
Mono County	46.5	Relatively Low	46.9	91.2	2.5	89.0
Modoc County	39.7	Very Low	44.8	92.9	1.1	68.8
Sierra County	31.5	Very Low	37.7	95.6	2.4	66.8
Alpine County	10.6	Very Low	11.2	89.1	1.1	53.0

Frequently Asked Questions

How many California county records are included?

RiskByCounty includes 58 California county records from FEMA NRI v1.20 (December 2025).

Which FEMA county ratings appear in California?

FEMA NRI v1.20 (December 2025) county rating counts for California: Very Low: 3; Relatively Low: 7; Relatively Moderate: 17; Relatively High: 22; Very High: 9; Not available: 0.

How complete are the five selected hazard fields for California?

FEMA NRI v1.20 (December 2025) availability among 58 county records: Flood: 58 of 58; Wildfire: 58 of 58; Tornado: 58 of 58; Earthquake: 58 of 58; Hurricane: 8 of 58. RiskByCounty displays five selected hazard categories out of FEMA's 18.

Official Ready.gov resource

Continue to Ready.gov for federal emergency-planning information maintained outside RiskByCounty.

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Data Source

County data sourced from FEMA National Risk Index v1.20, released December 2025. Values are labeled NRI score (0–100 relative scale). RiskByCounty displays five selected hazard categories out of FEMA's 18; flood is the higher of the Coastal Flooding and Inland Flooding source scores.

RiskByCounty presents county-level source fields and deterministic arithmetic summaries.

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