Great Lakes Coastal Flood Hazard Studies

Federal Emergency Management Agency logoThe Federal Emergency Management Agency (FEMA) has initiated a coastal analysis and mapping study to produce updated Digital Flood Insurance Rate Maps (DFIRMs) for coastal counties around the Great Lakes. This storm surge study is one of the most extensive coastal storm surge analyses to date, encompassing coastal floodplains in eight states. Ultimately, the study will update the coastal storm surge elevations for all of the U.S. shoreline of the Great Lakes.

The updated coastal flood study will provide a better estimate of coastal flood hazards and risk for the Great Lakes. The current, or effective, Flood Insurance Rate Maps (FIRMs) are outdated primarily due to the age of data and methodologies, many of which date back to the 1970s. Major changes in National Flood Insurance Program (NFIP) policies and methodologies have occurred since the effective dates of many Flood Insurance Studies (FIS) in the area, creating the need for an update that would reflect a more detailed and complete hazard determination. For more information on the study, please visit http://www.greatlakescoast.org/great-lakes-coastal-analysis-and-mapping/.

Preliminary FIRMs are available for some coastal counties in Michigan on FEMA’s Flood Map Change Viewer.  This can be found online at https://www.msc.fema.gov/fmcv.   The Flood Map Change Viewer is updated as new FIRMs become available.

Public outreach is an important part of the study. Meetings are held with local officials and the public from each coastal county being remapped to provide information on the study and to solicit existing data that could be used. FEMA calls this process "Discovery", and documents the results in a report.

FEMA's Discovery Reports provide users with a comprehensive and holistic understanding of historical flood risk, existing coastal data, and current flood mitigation activities within each lake's basin. The Discovery Report also provides users with a summary of FEMA's intent to proceed with a coastal flood hazard study under FEMA's Risk Mapping, Assessment, and Planning (Risk MAP) program and the Great Lakes Coastal Flood Study (GLCFS) project.

To view or download a Discovery Report, go to https://www.greatlakescoast.org/great-lakes-coastal-analysis-and-mapping/outreach/discovery-reports/.