An Awesome New Tool for Mapping Coastal Flood Risk

Posted by on Apr 30, 2015

Storm surge risks in the Sarasota region shown in NOAA's Coastal Flood Exposure Mapper

Storm surge risks in the Sarasota region shown in NOAA’s Coastal Flood Exposure Mapper

The National Oceanic and Atmospheric Administration (NOAA) has just released an amazing online tool for mapping coastal flood risk. Coastal Flood Exposure Mapper allows users to examine, in great detail, the vulnerability to flooding of any location along the Atlantic or Gulf Coast. (The tool does not yet cover the Pacific Coast or inland riverine flooding.)

From the Coastal Flood Exposure Mapper main selector page most users will first want to check out the flood hazard maps.

You can view, for a region, a composite of coastal flood hazards, or individual components: shallow coastal flooding (impacts from exceptional high tides without storm effects), FEMA flood zones (both 1% or 100-year flood zones and .2% or 500-year flood zones), storm surge, and sea level rise. With all of these map options, you can vary the opacity of the layers to make it easier to see the underlying detail, and you can show or not show the legend. And you can zoom in or zoom out to show more or less detail, even down to individual streets.

There are very clear information windows that provide clear, succinct explanations of the map features, such as understanding the high-risk (1%) and moderate-risk (0.2%) FEMA flood zones. In the information window under “Shallow Coastal Flooding,” there’s a great animated instructional video that explains what this issue is all about.

The website includes a section on Tips that explains how this resource can be used effectively in public meetings. And the Resources section includes a selection of useful sites to delve into greater details—but not so much as to be overwhelming. You’ll also find some case studies and an FAQ link (though for some reason the FAQs are in a PDF that downloads).

Sea level rise in the Norfolk - Virginia Beach area. Source: NOAA Coastal Flood Exposure Mapper

Sea level rise in the Norfolk – Virginia Beach area. Source: NOAA Coastal Flood Exposure Mapper

Societal, infrastructure, and ecosystem impacts

The flood hazard mapping isn’t all you’ll find in this resource. To see how these coastal flood hazards might affect people, you can go back to the main selector page and choose Societal Exposure. There you get layers for Population Density, Poverty, Elderly, Employees, and Projected Population Growth, each of which you can explore to understand how coastal flooding will affect people living and working in that area, or the expected population growth.

To learn about impacts to infrastructure, you can click on Infrastructure Exposure and explore maps showing Development, Critical Facilities, and Development Patterns. This information will be more useful when you have zoomed in, rather than showing a large region.

Finally, to look at impacts coastal flooding will have on ecosystems, you can click on Ecosystem Exposure from the main selector page and take a look at Natural Areas and Open Space, Potential Pollution Sources, and Protection.

With all of these special-focus maps there are useful explanations found by clicking on the “i” icons.

FEMA flood zones in Lower Manhattan. Source: NOAA Coastal Flood Exposure Mapper

FEMA flood zones in Lower Manhattan. Source: NOAA Coastal Flood Exposure Mapper

Making the most of this mapping resource

The Coastal Flood Exposure Mapper has features for saving and sharing maps. For example, if I want to let relatives living in Virginia Beach know about flood hazards there, I can create and share such maps. Or if I’m consulting on a development project in coastal Alabama, I can create maps specific to that site.

If you’re at all involved with assessing or communicating flood hazards and resilience, I highly recommend spending some time with NOAA’s Coastal Flood Exposure Mapper. In my opinion, there’s no more useful resource out there to help us understand flood hazards in coastal locations—at least for the Atlantic and Gulf Coasts.

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Along with founding the Resilient Design Institute in 2012, Alex is founder of BuildingGreen, Inc. To keep up with his latest articles and musings, you can sign up for his Twitter feed. To receive e-mail notices of new blogs, sign up at the top of the page.


  1. Great tool!
    We are already using it for presentations tomorrow in Portland, Maine on coastal hazards.


  2. Your website and posts are compelling; risks to buildings and infrastructure are not respected enough by all stakeholders. My recent post titled “Rick Architects” may also be of interest to the resilient design community and readers of your blog:


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