The Federal Emergency Management Agency has been working for more than a decade on a program to re-map low-lying parts of the United States and bring the flood maps for the agency's National Flood Insurance Program (NFIP) into more precise conformance with the nation's terrain and flood risk. But progress in the poorly-funded program has been slow and halting. New maps take years to create and introduce, including a time-consuming review and appeal process. Even within a single state, not every county gets updated maps at the same time.

The Beaufort Gazette took a deep dive into the flood map topic in December, with Hurricane Matthew's intense flooding still fresh in the mind (see: "Beaufort County still has decades-old flood maps. Here’s why it matters," by Kelly Meyerhofer). "State and federal authorities have failed to update Beaufort County’s flood maps—which are more than 20 years old—despite the fact that funding for the project has been secured for over a decade, an investigation by The Island Packet and The Beaufort Gazette has found," the paper reported. "Beaufort and Jasper counties are the only two counties in South Carolina that haven’t even received a preliminary map from the S.C. Department of Natural Resources, according to a federal map database, even though Beaufort County leads statewide in the number of flood insurance policies. More than 50,000 property owners in Beaufort County—half on Hilton Head Island alone—have a policy, Federal Emergency Management Agency data shows."

New maps typically add some houses to the official floodplain and remove others. Homeowners in the affected locations are usually focused on the requirement for flood insurance that goes along with a floodplain designation. But flood zones also affect building codes for new construction and major remodels in the floodplain. A flood zone designation carries with it a requirement for elevation of the first occupied floor above the base flood elevation (BFE). If municipalities don't apply flood-related code provisions, property owners in that jurisdiction won't qualify for flood insurance—and by extension, won't qualify for federally insured mortgages. New maps change that game board.

"Beaufort and Jasper counties were actually among the first in the state to start the remapping process," the Gazette reported. "The S.C. DNR secured federal funding for Beaufort County in August 2005 and expected the project to take approximately five years, Lamm said. But 11 years have passed, and still there are no new maps."

Beaufort's flood risk, of course, is not just theoretical. In 1893, the county was heavily impacted by the so-called "Sea Islands hurricane," which made landfall near Savannah, Georgia, devastated the South Carolina coast, and traveled northward, causing major damage as far north as Maine. The current official flood zone includes 61% of Beaufort County, the Island Packet noted in 2014 (see: "New interactive storm-surge map helps residents see potential flood risks," by Rebecca Lurye). But in a worst-case scenario, many other parts of the county, beyond the so-called "100-year" flood zone, could also be inundated.