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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.


A flooded farm field. Image Copyright © Michael Collier. http://www.earthscienceworld.org/images

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.   Read more

Frequently Asked Questions

National Oceanic and Atmospheric Administration
U.S. Geological Survey
American Geosciences Institute

Latest News

Mammatus clouds that are usually associated with thunderstorms.
November 14, 2017 Following months of debate on the floor continuing late in the day on November 14, the House of Representatives passed legislation that would reauthorize the National Flood Insurance Program (NFIP) for five more years, while making several operational changes. According to the...
NASA hurricane satellite image
August 29, 2017 In anticipation of Hurricane Harvey making landfall on the Gulf Coast, the U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) were preparing for the massive storm by monitoring its...
NASA hurricane satellite image
April 18, 2017 The Weather Research and Forecasting Innovation Act (H.R.353) was signed into law by President Trump on April 18. This law prioritizes U.S. leadership in weather forecasting and research by authorizing new forecasting programs and support existing programs. The bill primarily focuses...
Flooding webinar postcard. Image Credit: AGI
Join hundreds of attendees from around the world for an in-depth discussion on assessing, mitigating, and communicating flood risk tomorrow, Wednesday, February 8, 2017 at 1:00pm EST. Register here. More info below.   This webinar features experts from federal and state government, who will...
Screenshot of the Marine Cadastre National Viewer. Image Credit: NOAA, BOEM
The American Meteorological Society (AMS) Policy Program’s workshop, “Opportunities and Needs in Integrated Water Prediction, Risk Assessment, and Management for Coastal Resilience,” concluded on September 28th, providing insights to coastal scientists and managers on how to better serve their...
Screenshot of the USGS Coastal Change Hazards Portal map
On September 27th and 28th, our Critical Issues intern attended a workshop hosted by the American Meteorological Society (AMS) Policy Program: “Opportunities and Needs in Integrated Water Prediction, Risk Assessment, and Management for Coastal Resilience.” The first day focused on resilience issues...
Interactive map of Texas Gulf shoreline change rates. Image Credit: Bureau of Economic Geology, University of Texas
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared an interactive map of shoreline change rates along the Texas Gulf Coast from the Bureau of Economic Geology at the University of Texas Jackson School of Geosciences (@txgeosciences), which you can find at http://bit.ly/1GoF214...
August 2016 Statewide Precipitation Ranks. Image Credit: NOAA
The National Oceanic and Atmospheric Administration (NOAA) held their latest Monthly Climate Briefing on September 15, 2016, and we have summarized the highlights for you below: •  August 2016 is the 17th warmest (73.6°F, 1.5°F above average), 2nd wettest August (3.47", 0.85" above average) since...
NASA hurricane satellite image
August 16, 2016 The National Oceanic and Atmospheric Administration (NOAA) recently launched its National Water Model (NWM), a new hydrologic model that the agency claims will yield the “biggest improvement in flood forecasting the country has ever seen.” The new model will allow NOAA’s National...
AGI's Geoscience Policy Program published the May 2016 Summary of federal-level legislation impacting the geoscience community. This includes continuing appropriations discussions in both the House and Senate for funding in FY 2017 for agencies that employ geoscientists, studying geoscience...

Case Studies & Factsheets


Introduction Dry wells improve stormwater drainage and aquifer recharge by providing a fast, direct route for rainwater to drain deep into underlying sediment and rock. Dry wells are most common in the western U.S. where clay or caliche layers slow down the natural drainage of water into...


What is a Dry Well? A dry well is a well that is used to transmit surface water underground and is deeper than its width at the surface (see image, below). Most dry wells are 30 to 70 feet deep and 3 feet wide at the surface. They are lined with perforated casings and can be filled with gravel...

Pre-Ike (left) and post-Ike (right) ASTER imagery of Galveston Island, the Bolívar Peninsula, and the mainland in August 2006. Healthy (red) and dead (brown) vegetation shows storm surge inundation effects. Image Credit: Jesse Allen, NASA Earth Observ.

Defining the Problem Hurricanes bring not only intense rainfall, but also high winds and flooding. This flooding is powered by the hurricane storm surge: a rise in coastal sea level caused by lowered barometric pressure and by wind blowing the ocean onto the land. The result is that waves and...

GOLI Online Courses

GOLI Course: Assessing, Mitigating, and Communicating Flood Risk. Image courtesy of Maria Coxx Lamm
Course Type: GOLI Online Course

Flooding is a perennial hazard for rivers and coasts alike. Every year, flooding results in billions of dollars of damage and the loss of dozens to hundreds of lives across the United States. Efforts to mitigate this hazard rely on the work of geoscientists, planners, and communicators to assess...

GOLI Course: Planning for Coastal Storm and Erosion Hazards; Image credit: USGS/USFWS - photo by Greg Thompson
Course Type: GOLI Online Course

Coastal hazards are a widespread challenge that cost millions (and sometimes billions) of dollars in the U.S. every year due to property loss and spending on mitigation measures. Based on the most recent U.S. Census, over 39% of the U.S. population lives in areas that may undergo significant...

Research Database Publications

Cover of O-2015-05; Source: Oregon Department of Geology and Mineral Industries (DOGAMI)
2015, Oregon Department of Geology and Mineral Industries (DOGAMI)
The objective of the Clatsop County coastal flood hazard project is to develop updated Digital Flood Insurance Rate Maps (DFIRM) and Flood Insurance Study (FIS) report for Clatsop County, Oregon (Figure 1-1). For this effort, the Oregon Department of Geology and Mineral Industries (DOGAMI) will be...
Cover of FS-014 ; Source: Oregon Department of Geology and Mineral Industries (DOGAMI)
2014, Oregon Department of Geology and Mineral Industries (DOGAMI)
The Federal Emergency Management Agency (FEMA) publishes Flood Insurance Rate Maps that identify special flood hazard areas where flood insurance is required for structures with federally backed mortgages. Many of the rate maps for Oregon haven’t been revised since the 1970s and 1980s, and may...
Cover of SIR2015-5036; Source: U.S. Geological Survey
2015, U.S. Geological Survey (USGS)
The hybrid cyclone-nor’easter known as Hurricane Sandy affected the mid-Atlantic and northeastern United States during October 28-30, 2012, causing extensive coastal flooding. Prior to storm landfall, the U.S. Geological Survey (USGS) deployed a temporary monitoring network from Virginia to Maine...
Cover of ofr2016-1198; Image credit: U.S. Geological Survey
2017, U.S. Geological Survey (USGS)
Heavy rainfall during December 2015 resulted in flooding across parts of Arkansas; rainfall amounts were as high as 12 inches over a period from December 27, 2015, to December 29, 2015. Although precipitation accumulations were highest in northwestern Arkansas, significant flooding occurred in...
Cover of fs2016-3073; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
The Souris River Basin is a 61,000 square kilometer basin in the provinces of Saskatchewan and Manitoba and the state of North Dakota. Record setting rains in May and June of 2011 led to record flooding with peak annual streamflow values (762 cubic meters per second [m3/s]) more than twice that of...
Cover for USGS FS 2014-3062 ; Source: USGS
2014, U.S. Geological Survey (USGS)
This fact sheet describes how the USGS is combining interdisciplinary science with state-of-the-art technologies to achieve a comprehensive understanding of coastal change caused by Hurricane Sandy. By assessing coastal change impacts through research and by developing tools that enhance our...
Cover of Flooding factsheet; Image credit: The Geological Society
2016, The Geological Society of London (GSL)
How many types of flood are there? Why does flooding happen, and how can we protect ourselves? This fact sheet, produced for a broad general audience, gives an overview of flooding categories, and how we can mitigate their effects.
Cover of O-2015-06; Source: Oregon Department of Geology and Mineral Industries (DOGAMI)
2015, Oregon Department of Geology and Mineral Industries (DOGAMI)
The objective of the Lincoln County coastal flood hazard project is to develop a digital flood insurance rate map (DFIRM) and flood insurance study (FIS) report for Lincoln County, Oregon (Figure 1-1). A parallel effort is underway to convert the existing Lincoln County Federal Emergency Management...
Cover of fs2016-3023 ; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
Urbanization affects streamflow characteristics, coastal flooding, and groundwater recharge. Increasing impervious areas, streamflow diversions, and groundwater pumpage are some of the ways that the natural water cycle is affected by urbanization. Assessment of the relations among these factors and...
Cover of PP1821: Source: USGS
2015, U.S. Geological Survey (USGS)
Flooding in the Northeastern United States during 2011 was widespread and record setting. This report summarizes peak streamflows that were recorded by the U.S. Geological Survey (USGS) during separate flooding events in February, March, April, May, July, August, and September. The flooding of late...