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Storm-surge risks to property: Report looks at a post-Sandy world

When we lived in Mount Airy, I once joked that in the event all the glaciers melted, we'd have beachfront property.

When we lived in Mount Airy, I once joked that in the event all the glaciers melted, we'd have beachfront property.

Since my efforts to be the Henny Youngman of climate change, we've had some serious weather: Hurricane Sandy in 2012, which followed Irene in 2011.

The greatest damage in New Jersey and New York was caused by storm surge - especially in New York City, even with precautions taken after the extensive flooding caused by Hurricane Irene.

A report by financial-services company CoreLogic outlines the potential risk of damage from hurricane storm-surge inundation on the Atlantic and Gulf Coasts. The data show more than 6.8 million homes on those coasts are at risk of damage, with a total reconstruction-cost value of more than $1.5 trillion.

This 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 value of those homes.

Despite the overall increases, the 2016 analysis shows a decrease in the extreme-risk category for both the number and value of homes at risk.

At the regional level, the Atlantic Coast has just under 3.9 million homes at risk of storm surge, with a total reconstruction value of $953 billion.

The Gulf Coast has slightly more than 2.9 million homes at risk, with $592 billion in potential exposure to total-destruction damage, CoreLogic said.

Texas and Florida, which have the longest coastal areas, consistently have more homes at risk than other states.

The CoreLogic analysis of the storm-surge danger in the Philadelphia metropolitan area says it has 165,940 homes within those storm-surge zones, with a reconstruction-cost value of $31.88 billion.

Of those homes, the analysis shows 5,291 are designated in the extreme-risk zone, meaning that they would be affected by all hurricane category levels.

New Jersey has a total of 94,643 extreme-risk homes, 180,269 at very high risk, 104,010 at high risk, and 89,901 at moderate risk. Reconstruction costs would be $468.82 million.

Pennsylvania has 852 houses in the extreme-risk category, 19,843 at very high risk, 36,071 at high risk, and 26,485 at moderate risk, with total reconstruction costs of $83.25 million.

Although CoreLogic does not explain Pennsylvania's situation specifically, the storm-surge danger is like that of Washington, which is affected by Category 5 hurricane-driven water up the Potomac River from Chesapeake Bay. The Delaware River would be similarly affected, as would its tributaries, especially the Schuylkill.

The storm-surge analysis complements Federal Emergency Management Agency flood-zone information in providing a snapshot of potential damage exposure at the property level.

Many properties outside designated FEMA flood zones are still at risk for storm-surge damage.

Standard FEMA flood zones are designed to identify areas at risk for freshwater flooding as well as storm surges, based on the likelihood of either a 100-year or 500-year flood event, said Tom Jeffery, CoreLogic senior risk scientist and an author of the report. They don't differentiate risk based on storm severity, and so don't accurately reflect the total extent of potential risk along coastal areas.

Jeffery said homeowners who live outside designated FEMA flood zones often don't carry flood insurance, given that there is no mandate to do so, and, therefore, they may not be aware of the potential risk that storm surges pose to their properties.