FEMA National Flood Insurance Program:  

"Flood risk can, and does, change over time. Flood risks change for many reasons: new development, changes in levee classification, and environmental changes, to name a few. As a result FEMA is updating flood hazard maps across the country. These new flood maps, also, known as Digital Flood Insurance Rate Maps (DFIRMs), show flood risk at a property-by-property level.

When new maps are issued, your risk may have changed as well along with your flood insurance requirements. If your property is mapped out of a high-risk area, your flood insurance costs will likely decrease. If you've been mapped into a high-risk area, you will be required to purchase flood insurance if your mortgage is through a federally regulated or insured lender. But you can save money with the Newly Mapped procedure and through a process known as grandfathering provided by the NFIP.

If you live near a levee, your flood risk may be higher than you thought. Hundreds of levees across the country no longer meet federal standards for protection, so when new maps are issued, these areas will be shown as high risk."

Learn More:

• FEMA Flood Map Modernization (Factsheet), Oregon Department of Geology and Mineral Industries
  Examples from Oregon of how flood map modernization can affect mapped flood zones.

• National River Observations (Website), National Weather Service
  Real-time information from 8000 stream gauges across the United States showing current river/flooding conditions, and forecasts where available.

• Flood Risk Products (Website), Federal Emergency Management Agency
  Flood risk products provided by FEMA to "help community officials and the public view and understand their local flood risk."

• Assessing, Mitigating, and Communicating Flood Risk (Webinar), American Geosciences Institute
  2017 Webinar on flood risk assessment, mitigation, and communication efforts in the U.S. from national to state and local levels - includes many additional resources on flood risk in your area