Atlantic, Gulf States, Metro Areas Ranked by Homes Exposed to Storm Surge: CoreLogic

More than 6.8 million homes on the Atlantic and Gulf coasts are in danger of hurricane storm surge damage. The total cost for reconstruction of the homes located in 19 states and the District of Columbia is more than $1.5 trillion, according CoreLogic’s latest storm surge report.

The property information and analytics provider’s 2016 Storm Surge Report release coincides with the June 1 start of the Atlantic hurricane season. Using more advanced and granular data than in previous years, the 2016 analysis shows an increase from 2015 in the overall number of homes at risk of storm surge as well as an increase in the reconstruction cost value (RCV) of these homes. Despite the overall increases, the 2016 more advanced analysis shows a decrease in the most extreme category for both the number and value of homes at risk.

Table 1 – Total Number of Homes at Risk Nationally and Estimated Reconstruction Cost Value

(Storm Category) Total Homes Potentially Affected Total Estimated

RCV

(U.S. Dollars) Extreme

(Category 1-5 storm) 813,587 $191,973,679,305 Very High

(Category 2-5 storm) 1,658,151 $398,669,536,279 High

(Category 3-5 storm) 2,006,258 $455,622,094,460 Moderate

(Category 4-5 storm) 1,471,389 $332,852,780,000 Low

(Category 5 storm) 880,799 $166,974,115,052 Total 6,830,184 $1,546,092,205,096

“Using more granular-level data has given us an even clearer picture of which homes are at risk of storm surge damage,” said Dr. Tom Jeffery, senior hazard risk scientist for CoreLogic. “Despite the overall increases in risk, we were glad to see that the number and value of homes in the most extreme, and dangerous, category actually declined. It just goes to show the power of how advanced data can improve risk assessment at the property level.”

At the regional level, the Atlantic Coast has just under 3.9 million homes at risk of storm surge with an RCV of $953 billion, and the Gulf Coast has just over 2.9 million homes at risk with $592 billion in potential exposure to total destruction damage (Table 2).

Table 2 – Residential Exposure by Coastal Region

At the state level, Texas and Florida, which have the longest coastal areas, consistently have more homes at risk than other states. Florida ranks first with 2.7 million at-risk homes across the five risk categories and Texas ranks third with 531,169 at-risk homes (Table 3). Since the number of homes at risk strongly correlates with the accompanying RCV, these two states rank first and fifth, respectively for having the largest RCV (Table 4). States with less coastal exposure but lower-lying elevations that extend farther inland, such as Louisiana (ranked second at 800,521 at-risk homes) and New Jersey (ranked fourth at 468,823 at-risk homes), tend to have more total homes at risk because of the potential for surge water to travel farther inland. Louisiana and New Jersey are also near the top of the list for RCV, with Louisiana totaling $184 billion (ranked second) and New Jersey totaling $139 billion (ranked fourth).

Table 3 – State at-Risk Totals (Ranked by the Number of Homes at Risk)

*The “Low” risk category is based on Category 5 hurricanes which are not likely along the northeastern Atlantic Coast. States in that area have N/A designated for the Low category due to the extremely low probability of a Category 5 storm affecting that area.

** Washington, D.C. has no Atlantic coastal homes, but can be affected by larger hurricanes that push storm surge into the Potomac River. Category 1 and 2 storms will likely not generate sufficient storm surge to affect homes in Washington, D.C.

Table 4 – Reconstruction Cost Value of Homes at Risk by State

At the local level, 15 Core Based Statistical Areas (CBSAs) account for 67.3 percent of the 6.8 million total at-risk homes and 68.3 percent of the total $1.54 trillion RCV (Table 5). This disproportionate distribution of homes suggests that the location of hurricanes that hit land is often a more important factor than the number of storms that may occur during the year. The Miami CBSA, which includes Fort Lauderdale and West Palm Beach, has the most homes at risk totaling 780,482 with an RCV of just under $144 billion. By comparison, the New York City CBSA has slightly fewer homes at risk at 719,373, but a significantly higher total RCV totaling $260 billion.

Table 5 – Storm Surge Risk for Top 15 Metropolitan Areas

(U.S. Dollars) 1 Miami, FL 780,482 $143,949,383,422 2 New York, NY 719,373 $260,195,234,842 3 Tampa, FL 454,746 $80,627,283,072 4 New Orleans, LA 390,806 $94,043,948,226 5 Virginia Beach, VA-NC 385,084 $83,472,805,334 6 Cape Coral, FL 306,953 $61,989,183,591 7 Houston, TX 280,112 $51,868,761,737 8 Bradenton, FL 250,615 $47,331,097,845 9 Naples, FL 180,919 $43,178,509,775 10 Jacksonville, FL 166,709 $35,807,031,655 11 Philadelphia, PA 165,940 $31,884,862,628 12 Charleston, SC 145,356 $36,193,547,227 13 Boston, MA 129,167 $38,480,093,842 14 Myrtle Beach, NC 123,645 $21,588,181,602 15 Lafayette, LA 119,942 $25,831,094,601 Total 4,599,849 $1,056,441,019,399

To illustrate varying degrees of flood risk exposure, the analysis compares homes that are not located within FEMA 100-year floodplains against the number of homes located in surge inundation zones, as well as those located in both surge and FEMA Special Flood Hazard Areas (SFHA).

The CoreLogic storm surge analysis encompasses single-family residential structures and also includes mobile homes, duplexes, manufactured homes and cabins, among other non-traditional home types. Year-over-year changes in the number of homes at risk and RCV can be the result of several variables, including new home construction, improved public records, enhanced modeling techniques, fluctuation in labor, equipment and material costs, and even potential rise in sea level. As a result, CoreLogic says direct year-over-year comparisons should be avoided.

To estimate the value of property exposure of the single-family residences, CoreLogic utilized its proprietary RCV methodology which estimates the cost to rebuild the home in the event of a total loss and is not to be confused with property market values or new construction cost estimation. Reconstruction cost estimates include the cost of materials, equipment and labor needed to rebuild, and also factor in geographical pricing differences. Actual land values are not included. The values are based on 100-percent or total destruction of the residential structure. Depending on the amount of surge water from a given storm, there may be less than 100-percent damage to the residence, which would result in a lower realized RCV.

This full CoreLogic report is available online.

All charts produced by CoreLogic.