Coastal Hazards

GIS mapping screenshot

Geographic information systems (GIS) are mapping tools used to integrate, store, edit, analyze, share, and display geographic information. NOS provides a variety of GIS data products to the coastal management community. Pictured above is the Sea Level Rise and Coastal Flooding Impacts Viewer that uses local elevation data and visualization software to allow users to see how one to six feet of sea level rise might affect their coastal communities.

Do you live on or near the coast? The odds are better than 50-50 that you do. In 2010, 52 percent of us lived in one of the nation's 673 coastal counties (excluding Alaska). It's no secret why so many of us choose to live in coastal regions. These are areas of great bounty and beauty. The downside? These areas are also prone to many natural hazards such as erosion, harmful algal blooms, big storms, flooding, tsunamis, and sea level rise.

Local and state governments are on the forefront of the effort to minimize the environmental, social, and economic havoc these hazards can wreak. And NOS is there to provide tools, information, and training to help these agencies keep communities safe and resilient.

Need help figuring out where to start? Try the Roadmap for Adapting to Coastal Risk for a participatory approach for assessing a community's vulnerability to hazards―and for incorporating relevant data and information about hazards and climate into ongoing local planning and decision-making.

Adapting to Climate Change

NOS is helping coastal communities develop strategies to prepare.

What can we expect from the climate in the coming decade? In the next century? How about hundreds of years from now? Scientists at NOAA and agencies around the world are actively researching these questions, but one thing is clear. We are experiencing the effects of climate change today — particularly in coastal communities.

One of the National Ocean Service's key roles is to help coastal communities develop strategies to prepare. NOS experts are working directly with state decision makers and planners to share knowledge, talk about issues, and help identify climate change-related risks and vulnerabilities in their communities.

The Office for Coastal Management (OCM), for example, offers a customizable workshop to teach local and state shoreline planners about climate change, as well as the planning processes and actions that can help their communities better prepare for an uncertain future.

Sea Level Rise

NOS is monitoring the rate of sea level rise to help us adapt to this change.

With the majority of us living in coastal states, one impact of climate change many of us should be concerned about is sea level rise. Scientists have determined that global sea level has been steadily rising since 1900 at a rate of 1.7 millimeters (.07 inches) per year. While this may not seem like a big change, even a small rise in water levels can have a big impact—from increased flooding to eroding shorelines and loss of wetlands.

How do scientists keep track of these changes in sea level in the U.S.? NOAA's Center for Operational Oceanographic Products and Services (CO-OPS) maintains a National Water Level Observation Network of 200 stations around the country. Monitoring the rate of sea level rise is an important component to helping us adapt to this change.

NOS is also measuring and helping people understand the magnitude of sea level rise on a local scale. CO-OPS provides a service called Sea Levels Online that serves up local rates of sea level rise for all U.S. coasts to help coastal decision makers understand and quantify risks. NOAA's Coastal Services Center also provides the Sea Level Rise and Coastal Flooding Impacts Viewer, which allows communities to visualize the potential impacts of sea level rise. After all, we can't plan for something if we don't know what to expect!

Coastal Storms

NOS is helping communities get ready for coastal storms.

The high winds, flooding, and erosion associated with coastal storms such as hurricanes and nor'easters pummel coastal communities every year. And scientists estimate that the frequency and intensity of these storms is only going to increase. That's kind of scary.

NOS is helping communities get ready for these storms so they will incur less damage and bounce back more quickly in the aftermath. For example, the Office for Coastal Management leads the Coastal Storms Program. This program brings together local, state, and federal organizations to deliver the specific tools, training, data, and other products to reduce the loss of life and other impacts from storms on communities and the environment.

The Center also offers a website called Historical Hurricanes Tracks, a resource that allows users to pinpoint historical hurricane information at specific geographic locations. With this tool, users can learn about the size and frequency of events that have occurred in their area of interest, coastal population growth over the past century, and hurricane-related damage estimates. Learning about past hurricane activity can help us prepare for the future.

In addition, the Center for Operational Oceanographic Products and Services issues a real-time Storm Quicklook during coastal storm events to provide emergency managers and the public with an integrated display of water level and meteorological conditions in a location impacted by a hurricane. Post-storm reports are also available, which summarize the extreme water level conditions associated with the storm.


NOS is helping to minimize loss of life and property caused by erosion.

While it might be nice to have a house that is close to the ocean, there is such a thing as being too close. Erosion—caused by storms, flooding, sea level rise, or the alteration of the shoreline—can cause beaches and coastal bluffs to wear away. And that can be bad news for our homes and infrastructure. How bad? Today, erosion is responsible for around $500 million in coastal property loss each year.

As required by the Coastal Zone Management Act, the Office for Coastal Management works with state coastal management programs to not only minimize loss of life and property caused by erosion, but to do so while protecting natural coastal resources. Accomplishing both things requires the development of shoreline management policies, regulations, and plans. The office, in partnership with NOAA's Restoration Center, offers a Shoreline Management Technical Assistance Toolbox to help coastal managers and local decision makers manage their shorelines. Effective shoreline management, such as the use of zoning, setbacks, education/outreach campaigns, relocation assistance, and/or land acquisition, can help to reduce, or avoid altogether, the need for costly erosion control structures. Effective shoreline management policies can also help maintain the natural shoreline dynamics and preserve important coastal environments.

Harmful Algal Blooms

NOS is helping to forecast HABs.

Coastal threats come in many forms. Harmful Algal Blooms—commonly referred to as ‘red tides'—are a good example of this.

Economic impacts of harmful algal blooms in the United States average $75 million annually including impacts on public health costs, commercial fishing closures, recreation and tourism losses, and management and monitoring costs.

When these events occur, NOS is there to help coastal states. For instance, the NOAA Harmful Algal Bloom Operational Forecast System provides alert bulletins to help predict HAB landfall for the states that border the Gulf of Mexico. How? NOS scientists can locate blooms by assessing surface chlorophyll concentrations detected by satellite imagery and verified by data from ships or along the shore. They then apply their understanding of the biological and physical aspects of bloom dynamics and transport and the conditions that are conducive for HAB development to predict when and where HABs will impact coastal communities.

If you don't live near the Gulf of Mexico, stay tuned. HAB forecasts are in various stages of development in other parts of the nation.  The Harmful Algal Bloom Operational Forecast System is operated by the Center for Operational Oceanographic Products and Services — the nation's authoritative source for accurate, reliable, and timely water-level and ocean current measurements. The forecasting system is also produced in close partnership with NOAA's National Centers for Coastal Ocean Science.

Would you like to know more about HABs? You're in luck!

Hypoxia & Eutrophication

NOS studies hypoxic zones to help restore and protect coastal ecosystems.

Have you ever heard of the phrase 'dead zone?' No, we're not talking about a B-movie horror flick. We're talking about a phenomenon called 'hypoxia,' which refers to a reduced level of oxygen in the water. Less oxygen dissolved in the water is often referred to as a "dead zone" because most marine life either dies, or, if they are mobile such as fish, leave the area. Habitats that would normally be teeming with life become, essentially, biological deserts.

Hypoxic zones can occur naturally, but scientists are concerned about the areas created or enhanced by human activity. Nutrient pollution—known as eutrophication—is the primary cause of those zones created by humans. Excess nutrients that run off land or are piped as wastewater into rivers and coasts can stimulate an overgrowth of algae, which then sinks and decomposes in the water. The decomposition process consumes oxygen and depletes the supply available to healthy marine life. Dead zones occur in many areas of the country, particularly along the East Coast, the Gulf of Mexico, and the Great Lakes, but there is no part of the country (or the world for that matter) that is immune.

NOS is involved with many activities to study, monitor, and predict hypoxic zones to help natural resource managers restore and protect coastal ecosystems. The National Centers for Coastal Ocean Science, which administers the nation's only federal-level hypoxia program, is at the forefront of this effort. The goal of these efforts involve collecting vast amounts of sampling data from our hypoxia-prone coastal waterways, synthesizing this information, and producing complex computer models to understand how these zones are forming—and how they may form in the future. Knowing how these zones form in different parts of the country is also key in helping decision-makers target which activities on land need to curbed to best reduce this threat.

Check out podcasts on eutrophication and hypoxia to learn more straight from NOS experts.


NOS provides real-time coastal water level data, critical for tsunami warnings and forecasts.

NOS' primary role in tsunami warning is to provide real-time coastal water level data to NOAA's Tsunami Program and the public, which is critical to issuing warnings and forecasts during an event.

High-frequency water level information is also important to tsunami modeling, both during and after an event, to refine the forecasts as the event progresses, and to better understand tsunami science for future improvements to the National Tsunami Warning System.

The Hawaii Tsunami Information Service App developed by the Office for Coastal Management teaches users about tsunami warning signs and provides easy-to-understand evacuation maps, instructions, and information to help prepare for disaster. The free app is available for download from iTunes or the Google Play Store.

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