CoreLogic has released its 2013 CoreLogic Storm Surge Report featuring updated estimations on both the number and value of single-family homes exposed to hurricane-driven storm-surge damage within the United States. According to this year's analysis, more than 4.2 million homes along the U.S. Atlantic and Gulf coasts are located within storm-surge risk zones, totaling more than $1.1 trillion in property exposure.
The CoreLogic Storm Surge Report, issued annually, provides a breakdown of residential property risk along the Atlantic and Gulf coasts at five key geographic levels - national, regional, state, metro and ZIP code. The 2013 findings reflect a significant increase in both the number of total properties at risk, as well as total value. This year's report features an enhanced methodology using CoreLogic Automated Valuation Model (AVM) data that improves the accuracy of the analysis. New this year, the report also provides an estimation of the potential increase in risk based on theoretical future rises in sea level.
"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," said Dr. Howard Botts, vice president and director of database development for CoreLogic Spatial Solutions. "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."
In fact, also this year, the Federal Emergency Management Agency (FEMA) released preliminary revised flood maps that increase the scope of designated flood zone areas in several New York City suburbs to include 35,000 additional homes and businesses not previously identified as existing within a flood zone.
CoreLogic publishes the annual Storm Surge Report to enhance understanding of the additional risk hurricane-driven storm surge poses to homes located in areas prone to tropical storms. Storm surge is triggered primarily by the high winds and low pressure associated with hurricanes, which cause water to amass inside a storm as it moves across the ocean before releasing as a powerful rush overland when the hurricane moves onshore. In addition to the property damage and potential lives lost to flooding, the speed and force associated with storm-surge waves can significantly increase geographic and economic impact in hurricane disaster areas.
Key highlights of the 2013 CoreLogic analysis include:
There are more than 4.2 million residential properties exposed to storm-surge risk valued at roughly $1.1 trillion, with more than $658 billion of that risk concentrated in 10 major metro areas.
Florida tops the state rankings with nearly 1.5 million properties at risk and $386 billion in total potential exposure to damage.
Louisiana ranks second in total properties at risk with just over 411,000 homes in storm-surge zones. New York ranks second in total value of coastal properties exposed at nearly $135 billion. At the local level, 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.
For the first time, the 2013 CoreLogic Storm Surge analysis addresses the potential impact of a climate-related rise in sea level on coastal storm-surge risk in a select number of metro areas. These findings show that the Miami area could potentially have the highest increase in the number of homes at risk of the cities discussed in the report. Given 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.
"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," said Botts. "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. 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."
Also significant in the 2013 findings is the noticeable number of properties in the New Orleans area that were previously located in an "Extreme Risk" zone and that have now been downgraded to the "High Risk" zone between 2012 and 2013. This dramatic shift is a direct result of the recent completion of a new protective levy system by the Army Corps of Engineers developed 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. 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," said Botts. "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."
This is the fourth annual CoreLogic Storm Surge Report. The concepts in the report complement Federal Emergency Management Agency (FEMA) flood zone information to provide a comprehensive picture of potential damage exposure at the property level, as many properties located outside designated flood zones are still at risk for storm-surge damage.
Important to note is that the total properties and structural values included in the CoreLogic analysis are based on all homes that could potentially be damaged from hurricane-driven storm surge, and are not meant to infer that a single storm or storms in a specific hurricane season will result in these damage totals.