The mid-Atlantic region is expected to see the most dramatic increase in the country in flooding over the next 30 years, driven by an increasing northern reach of hurricanes due to rising temperatures in the atmosphere and oceans, a nonprofit research group says.
And, for New Jersey, that includes tens of thousands more properties affected than federal numbers would suggest.
In fact, Virginia, Delaware and N.J. are ranked highest for the biggest impact among the 48 contiguous U.S. states. The risk for Philadelphia and other Pennsylvania municipalities also rises substantially.
The First Street Foundation’s first annual National Flood Risk Assessment, released Monday, was compiled by scientists who say they developed a “high precision, climate adjusted” online Flood Factor tool for property owners. The tool ranks properties on a score of 1 to 10, based on a risk of flooding over 30 years.
The tool allows people to assess the risk for 142 million properties in the U.S.
The Federal Emergency Management Agency classifies 8.7 million properties as having substantial risk within Special Flood Hazard Areas based on past and present flood risk. But First Street Foundation’s modeling identified 14.6 million properties with that risk, or nearly 6 million more.
The top five states currently showing the greatest proportion of properties with substantial flood risk — meaning a bigger percent of a community is exposed to risk — include West Virginia, Louisiana, Florida, Idaho and Montana. The authors found that flood risk is changing for not only coastal states, but inland states too because of shifting patterns of precipitation.
By 2050, the number of properties facing substantial risk in the U.S. will increase by 10.9% to 16.2 million due to climate change and sea-level rise, the researchers found.
“Sea-level rise is exposing an increasing number of coastal properties to flooding from extreme high tides and storms,” said Robert Kopp, director of the Rutgers Institute of Earth, Ocean, and Atmospheric Sciences. Rutgers led the development of the sea-level rise projections used in the analysis.
Coastal states also face increased risk from sea-level rise and surge due to tropical storms and hurricanes. The modeling shows New Jersey with 73,600 more properties at substantial risk in 2050 than are included in current FEMA flood risk assessment maps.
The Jersey Shore in particular is threatened by major recurrent flooding, high tide flooding, and storms. New Jersey is also affected by sea level rise exacerbated by gradually sinking land.
In total, First Street’s Flood Model suggests there are 617,300 properties in New Jersey at risk over the next 30 years. Of those, 150,700 are categorized as facing almost certain risk, with a 99% chance of flooding at least once over the next 30 years.
The report says Ocean City has the greatest number of properties at risk of flooding.
First Street has singled out Ocean City in the past as a prime flood risk, something city officials have taken issue with.
Last year, First Street released a report stating Ocean City faced the highest projected property loss in the state. At the time, Mayor Jay Gillian said the 2019 report contained “misleading information” about the city’s property values and tidal flooding. He also said the group’s estimation of theoretical losses in real estate values were “implausible.”
Gillian could be reached immediately for comment Monday.
However, smaller municipalities, such as Wildwood, may have a greater proportion of property where researchers say 98% of properties are at risk.
The report says 588,700 property owners in New Jersey have made flood damage claims through FEMA since the year 2000. The greatest number of claims, which would include Hurricane Sandy in 2012, have been concentrated in Ocean, Monmouth, Middlesex, Union, and Essex counties.
In Pennsylvania, the report says Philadelphia has the greatest number of properties at risk of flooding with 53,400 currently at risk, or 10% of its total number of properties. But, smaller municipalities might have a greater proportion of total properties at risk. For example, Folcroft in Delaware County, bordered by Darby Creek, will experience a 56% increase in the number of properties at risk over the next 30 years, the report states.
The modeling was conducted by researchers and hydrologists from First Street Foundation, which include scientists from Columbia, George Mason, MIT, Rutgers, Berkeley, and Bristol in England.