4.2 million U.S. homes at risk of hurricane storm surge: report

More than four million United States homes, with a combined value of over $1 trillion, are at risk of hurricane storm surge damage, according to a new report from analytics firm CoreLogic.

The firm estimates that 4.2 million single-family home along the U.S. Atlantic and Gulf coasts are at risk, half a million of which are in the New York metropolitan area alone, according to its 2013 Storm Surge report.

“Public awareness of the risk hurricane-driven storm surge poses to coastal homeowners has never been higher coming off the heels of Hurricane Sandy last fall,” Howard Botts, vice president and director of database development for CoreLogic Spatial Solutions noted in a statement.

“Sandy was a harsh reminder of the potential destruction associated with storm-surge flooding, and of just how many communities are vulnerable to that risk, in areas typically assumed to be relatively safe from hurricanes along the northeastern Atlantic shoreline,” he added.

This year, the Federal Emergency Management Agency (FEMA) also released revised flood maps that include 35,000 more additional homes and businesses in several suburbs of New York City that hadn’t previously been included in flood zones, CoreLogic noted.

Of the homes included as at risk in the report, more than $658 billion of the exposure is concentrated in 10 major metro areas, according to CoreLogic’s research.

Florida tops the state rankings with nearly 1.5 million properties at risk and $386 billion in total potential exposure to damage, followed by Louisiana, where about 411,000 homes are in storm-surge zones.

New York ranks second in terms of total value, with its exposed properties valued at nearly $135 billion, CoreLogic said.

The New York metropolitan area, which encompasses northern New Jersey and Long Island as well, contains not only the highest number of homes at risk for potential storm-surge damage, but also the highest total value of residential property exposed, at more than $200 billion, the firm noted.  

The report also looks at the potential impact of a climate-related rise in sea levels. Its analysis suggests that the Miami area could possibly have the highest increase in the number of homes at risk in terms of storm surge.

With a one-foot rise in sea level, total properties at risk would nearly double from just under 132,000 to almost 340,000, and estimated value would increase from an estimated $48 billion to more than $94 billion overall, according to CoreLogic.

“One recurring question in storm-surge analysis is whether or not climate change is affecting the development of hurricanes and causing an increase in the frequency or intensity of these events,” Botts noted.

“Though the CoreLogic Storm Surge Report is not designed to address that specific question, we do consider a potential rise in sea level as a crucial contributing factor to the full extent of coastal storm-surge risk and have expanded the analysis to include projected increases in risk associated with a hypothetical one-foot, two-foot and three-foot rise,” he said.

“The geographic location and characteristics of an urban area along the coast will naturally contribute greatly to the level of risk resulting from a potential sea-level rise, as is the case in Miami with lower elevation and close proximity to ocean water,” he added.

However, the company also notes that some homes in the New Orleans area that were previously located in “Extreme Risk” areas have been downgraded to “High Risk” areas, as a result of a new levy system developed by the Army Corps of Engineers in the aftermath of Hurricane Katrina.

“As the report analysis shows, the efforts to build and enhance flood barriers in New Orleans after Katrina have improved the ability of the city to protect more properties from low-and mid-level hurricane-driven surge,” Botts said.

“This added protection doesn’t completely eliminate risk to homes in the area, but it does demonstrate how mitigation efforts afford a level of protection against certain storm levels,” he noted.

“As Hurricane Sandy and recent history have made clear, the full extent of potential storm-surge risk is not often understood, especially in areas thought to be less common targets for hurricanes.”