San Diego County, CA flood risk and hazards

San Diego County in the state and national rankings

At about $1.54 billion, modeled expected annual loss in San Diego County ranks #11 of 3,232 across the US. Its share of California modeled loss is 5.1%, with a state rank of #7 of 58. The modeled $1.54 billion annual average does not predict the loss in any single year. The next higher national total is about $1.68 billion, in King County, WA. Dallas County, TX ranks immediately below it, with about $973.2 million in modeled annual loss. Within the state list, Alameda County, CA has the next higher estimate: about $1.88 billion. Its 6.2% state loss share accompanies an estimate about $345.6 million away from this county’s total. At about $970.5 million, Contra Costa County, CA is one place lower in the state loss ordering. Its 3.2% state loss share accompanies an estimate about $568.6 million away from this county’s total.

California county comparisons

San Diego County hazard estimates

Riverine Flood

For riverine flooding, about $647.6 million in expected annual loss puts the county #9 of 3,232 across the US. Its 42.1% share of total loss comes with a state loss rank of #6 of 58; FEMA assigns a Very High rating, matching 26 US counties, including 9 in California, for this hazard.

Wildfire

The largest US county estimate for wildfires belongs here: about $430.2 million, ranking #1 of 3,144. At 27.9% of the county’s modeled loss, the hazard places #1 of 58 statewide; FEMA assigns a Very High rating; the same rating for wildfires covers 4 California counties and 4 across the US.

Earthquake

With about $426.1 million in modeled expected annual loss from earthquakes, the county ranks #12 of 3,232 in the national comparison. In California, this estimate ranks #10 of 58 and represents 27.7% of the county’s modeled loss; FEMA assigns a Relatively High rating; the Relatively High label covers 20 state counties and 53 nationally for earthquakes.

Heat Wave

FEMA models about $24.2 million in expected annual loss from heat waves, placing the county #35 of 3,202 nationally. In California, this estimate ranks #4 of 58 and represents 1.6% of the county’s modeled loss; FEMA assigns a Relatively High rating; the same rating for heat waves covers 17 California counties and 98 across the US.

Landslide

The national loss rank for landslides is #45 of 3,222, based on about $3.1 million in modeled expected annual loss. This hazard makes up 0.2% of the total; FEMA assigns a Relatively High rating, and its loss ranks #9 of 58 in California, matching 65 US counties, including 27 in California, for this hazard.

Tornado

For tornadoes, about $2.3 million in expected annual loss puts the county #960 of 3,225 across the US. This hazard makes up 0.1% of the total; FEMA assigns a Relatively Low rating, and its loss ranks #6 of 58 in California; the Relatively Low label covers 14 state counties and 1,217 nationally for tornadoes.

For riverine flooding, modeled loss is about $217.5 million above wildfires, leaving 14.1 percentage points between their county shares. About $4.0 million separates wildfires from earthquakes in the local estimates, equivalent to 0.3 percentage points of county loss. For earthquakes, modeled loss is about $402.0 million above heat waves, leaving 26.1 percentage points between their county shares. About $21.1 million separates heat waves from landslides in the local estimates, equivalent to 1.4 percentage points of county loss. About $818,000 separates landslides from tornadoes in the local estimates, equivalent to 0.1 percentage points of county loss.

Population and recorded values

FEMA counts 3,295,981 residents in San Diego County, across about 4,571 square miles. For building value, the source records about $638.83 billion. About $1.07 billion is the agricultural value amount in FEMA’s record. Per resident, the modeled annual amount is about $467; the California average is about $764. The county holds 8.3% of the state population, compared with 5.1% of modeled loss. The county contains 8.2% of the building value recorded across California. Among 58 state county records with both inputs, its density stands at position 9 from highest to lowest. Those recorded totals give about 721 residents per square mile, versus about 239 across California. At 3,295,981 residents, the county compares with the California county median of about 186,448. In the US totals, the county represents 1.0% of modeled annual loss and 1.0% of recorded residents. Using the national population gives about $459 in modeled annual loss per person, versus about $467 here. The six hazards described above together make up 99.6% of modeled loss, about $1.53 billion annually. Other hazards account for the remaining 0.4% of modeled loss, about $5.8 million. In position 7 locally, tsunamis has about $1.6 million in modeled annual loss, ranking #11 of 20 statewide. This 0.1% slice of county loss ranks #54 of 119 across US counties. About $1.5 million places coastal flooding at number 8 in the local loss list and #9 of 21 within California. This 0.1% slice of county loss ranks #128 of 588 across US counties.

FEMA labels and risk score

San Diego County has a FEMA risk index score of about 99.7, ranking #10 of 3,144 nationally. FEMA labels risk index as Very High, matching 9 county records across California. The expected annual loss rating is Very High, a label shared by 7 of 58 California counties. The social vulnerability rating is Relatively Low, a label shared by 20 of 58 California counties. FEMA labels community resilience as Very Low, matching 12 county records across California. Its risk score ranks #7 of 58 within California, while its loss total ranks #7 of 58. Both ratings match in 3 counties statewide: vulnerability is Relatively Low, and resilience is Very Low. The group represents 19.0% of statewide loss; this county supplies 26.9% of the group’s modeled amount. With a score of about 99.7, Santa Clara County, CA ranks #6 of 58 statewide, immediately above this county. FEMA gives that county a Very High risk index label, alongside 6.5% of the state loss total. San Francisco County, CA is next below it by state risk score, at about 99.5; that record ranks #8 of 58. That comparison county holds a Very High risk index rating and 2.8% of California modeled annual loss. Nationally, 632 counties carry the same Relatively Low social vulnerability label, covering 30.0% of FEMA’s recorded population. FEMA lists 628 county records with Very Low community resilience; together they contain 18.6% of its US population total. The county’s Very High group contains 2 hazards: riverine flooding, wildfires. The county’s Relatively High group contains 3 hazards: earthquakes, heat waves, landslides. The county’s Relatively Moderate group contains 4 hazards: coastal flooding, hail, lightning, strong wind. Across the county’s hazard ratings, 4 carry Relatively Low: drought, tornadoes, tsunamis, winter weather. Across the county’s hazard ratings, 4 carry Very Low: avalanches, cold waves, hurricanes, volcanic activity.