A new flood model from the nonprofit First Street Foundation nearly doubles the number of properties the Federal Emergency Management Agency’s Special Flood Hazard Area had identified as at risk in a 1-in-100-year flood event.
In addition to looking at the potential for riverine and coastal flooding, as FEMA does, the First Street model, using recurrence intervals ranging from 1-in-2-year events to 1-in-500-year events, analyzes the effects of rainfall, sea-level rise and ungauged streams while incorporating climate change projections. Of those, “the biggest impact really is the sea-level rise because it’s pushing flood waters in the coastal areas into locations that previously did not flood,” says Mike Amodeo, director of data science at First Street Foundation.