High-risk flood zones are expanding this year along significant stretches of Florida’s coastline. In Broward County, nearly 90,000 properties have been moved into a FEMA flood zone. But 80,000 of them were in such a zone prior to ten years ago, when FEMA moved them out – only to add them back in this year. Many will now have to purchase flood insurance.

Former Florida Deputy Insurance Commissioner Lisa Miller talks with the county floodplain manager for an explanation, the reporter who broke the story, and another reporter from Palm Beach County, which is fighting FEMA’s efforts to expand flood zones.

Show Notes

FEMA calls these high-risk flood zones Special Flood Hazard Areas (SFHA). They are designated on a FEMA Flood Insurance Rate Map as zones that begin with the letter “A” or the letter “V” for those living along the coast, subject to additional threat of storm surge. Properties in these zones supposedly have a 1% probability of flooding each year, or about a one-in-four chance every 25-30 years. Some refer to this as the 1-in-100-year flood probability.

FEMA’s 2024 updated maps have moved nearly 90,000 (88,913) properties in Broward County, Florida into a high-risk flood zone. But almost 80,000 (79,689) were in that zone prior to FEMA’s 2014 map update, then removed, and now 10 years later are back in a flood zone. “How did this happen and what’s the science behind it?” asked host Miller.

Carlos Adorisio, Floodplain Manager for the unincorporated area of Broward County, explained that FEMA flood maps are based on studies of two factors: rainfall and coastal storm surge. Maps from the 1980’s and 1990’s reflected most of the county was high-risk. “In 2014, FEMA updated the maps, but they only updated the portion for the rainfall risk and not for the storm surge. There was a lot of development and better modeling and a lot of areas were removed from the 100-year floodplain,” he explained. In its 2024 maps, FEMA updated only the coastal storm surge risk. “There’s been more development, updated storm data, and better computer modeling techniques and mapping,” since the last storm surge studies done in the 1980’s, said Adorisio, who is a Professional Engineer and a Certified Floodplain Manager.

“One of the components of storm surge is the sea level, which is higher than they accounted for in the 80’s and therefore the storm surge is higher in this study,” Adorisio explained. “Now the southern part of the county is lower than the middle and northern sections of the county...and it's to the point where FEMA believes that the higher storm surge elevation not only goes to I-95, it goes all the way to U.S. 27, which is close to the Everglades levee. That’s why you have those almost 90,000 parcels that are increasing in flood risk and now in the Special Flood Hazard Area,” said Adorisio, who earlier in his career worked for FEMA as a technical consultant for flood maps.

Ron Hurtibise, business reporter for the South Florida Sun Sentinel, first reported the scope of the 2024 flood map changes. The new high-risk flood zones are primarily located along... (For full Show Notes, visit https://lisamillerassociates.com/episode-51-floridas-expanding-flood-zones/)