Group: Data show flood danger is underestimated
The federal government underestimates the flood risk for 370,194 households and properties in Pennsylvania, a wide-ranging scientific analysis said.
The First Street Foundation, a nonprofit organization that combined a series of contemporary flooding models into a single, nationwide flood risk tool, estimates that 564,589 properties in the state face a 1% annual chance of flooding. That threshold is the gold standard the federal government uses to assess which homeowners must purchase flood insurance and local planners use to determine which areas are safe to develop.
But under current federal flood maps, First Street found 194,395 properties in the floodplain, 190.4% less than in its model.
Experts say that places residents and property owners at an underappreciated risk to life and property.
In Allegheny and Philadelphia counties, 56,838 and 30,038 properties are at risk of flooding, respectively, but do not fall within the federal flood maps, the highest discrepancies in the state.
Philadelphia and Pittsburgh lead the way among cities, where a combined 45,889 properties face previously unidentified flooding risk.
9% increase in Reading?
Using the nonprofit’s FloodFactor website, Firststreet.org,
entry of ZIP code 19601 for Reading brought this response, in part: “Approximately 594 properties are already at risk in 19601, and within 30 years, about 648 will be at risk.” This is an increase of about 9%.
But 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 website will give a report for an address, ZIP code, city or state.
Nationally, the data say, 14.6 million properties are at risk of flooding. That’s nearly 6 million more than fall within current Federal Emergency Management floodplains, a 70% increase.
Particularly at risk are the most populated states.
In California, First Street calculated about 500,000 properties fall
within FEMA floodplains, or about 4% of the state’s total. But First Street calculated the actual number of properties at risk is nearly 1.1 million, more than double the federal government’s calculations and the largest discrepancy of any state.
Pennsylvania and New York follow, each with more than 370,000 additional properties at risk.
In addition to a presentday analysis, First Street’s modeling incorporated 2050 projections from the International Panel on Climate Change, the United Nations’ primary scientific body on the planet’s changing climate. The conclusion is another 1.5 million properties will be at risk of going underwater in 30 years, primarily along the Mid-Atlantic and Gulf Coast.
Federal flood maps offer no such future projections.