Housing and flood maps after María

After María, FEMA issued Advisory Base Flood Elevations for Puerto Rico, ABFE, referenced to the Puerto Rico Vertical Datum of 2002. The advisory maps were guidance for rebuilding, not an overnight replacement of every Flood Insurance Rate Map in force. FEMA's own language on the advisory services says they help communities understand the higher elevations to build to after the storm. They also say what they are not: a finished regulatory restudy in every neighborhood.

ABFE: advisory, post-disaster. NFHL: the digital National Flood Hazard Layer stack of in-force maps and map-change letters. Different products.

The National Flood Hazard Layer is the public digital stack of in-force flood maps. FEMA's flood map page and the Map Service Center remain the official doors. A house can sit in a pre-María rain zone, in a later advisory polygon, or both, depending on whether a restudy has become effective. Printing a single "the flood map" as if it were one sheet for the island is a real-estate fiction.

Housing after María was a pile of tarps, an insurance argument, a title argument, and a zone argument. Informal construction on hillsides and at river mouths met a storm that made the old drawings look optimistic. The advisory elevations tried to raise the conversation without waiting for a full restudy. People still went back to the same lots. A map not yet in force does not move a grandmother.

This is not a PREPA essay nor a death count. It is not a south coast drought map. Northern floodways can cross karst; southern ones can cross the dry belt. The hazard product remains FEMA's, dated after 2017, with advisory work in 2018, the year of this record.

USGS high-water marks after María exist in a separate open-file report. They anchor the water surface; they are not a FIRM.

If you rebuild, you want the in-force layer, the advisory elevation, and a surveyor who knows PRVD02. If you write, you want those names and a date. The rest is someone else's closing table. Landfall stops at the public door of the map.

Sources: FEMA, National Flood Hazard Layer. Freeze 2026-08-22.