Flood Basics

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A flooded farm field. Image Copyright © Michael Collier. http://www.earthscienceworld.org/images
A flooded farm field. Image Copyright © Michael Collier. http://www.earthscienceworld.org/images
  • A flooded farm field. Image Copyright © Michael Collier. http://www.earthscienceworld.org/images
  • Flooding at Heloden Lake in Montana. Image Copyright © Bruce Molnia, Terra Photographics

Flooding has many causes, including heavy rain, snow melting too fast, and dams or levees breaking. Coastal flooding occurs during hurricanes from heavy rainfall and storm surge, which causes sea level to rise temporarily at the shore.

Why do floods matter?

Flooding is the most common, and costliest, natural hazard facing the United States. Over the last 30 years, floods have caused an average of $8 billion in damages and 82 deaths per year nationwide.[1]

How does geoscience help inform decisions about flood hazards?

Geoscientists study water and fluid flow, monitor streamflow, and map out past flooding events and likely inundation zones to understand how and where flooding occurs and inform the public about flood risk. They also design structures to reduce flooding impacts and inform land-use managers and policy makers to establish best practices for flood management.

References

[1] Hydrologic Information Center - Flood Loss Data, National Weather Service, http://www.nws.noaa.gov/hic/

Learn More

Introductory Resources

  • Severe Weather 101: Flood Basics (Webpage) National Severe Storms Laboratory/NOAA
    Answers to basic questions about flood hazards, areas that are most at risk for flooding, and definitions of flood watches, warnings, advisories, statements.
     
  • Ready.gov - Floods (Webpage), FEMA
    Short article on flood hazards, what to do before/during/after flooding, flood insurance, and links to tools/resources on spring flooding.
  • 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.

Resources for Educators

Frequently Asked Questions

National Oceanic and Atmospheric Administration
U.S. Geological Survey
American Geosciences Institute
2017-05-18