Coastal Flooding

It is a strange sight for visitors, but for many residents it is becoming a part of daily life. These rulers are strategically placed in low lying areas to help residents deal with coastal flooding. They help drivers see if the water level is safe to plow through. Even on sunny days there can be standing water on the roads.

Sea level rise is rapidly increasing the number of these flood events throughout the year. For instance, the typical annual rate has doubled since 2000, from about 5 days to more than 10 days per year in 2018.

At the most basic level, coastal flooding occurs when water reaches a level that begins to impact coastal infrastructure. Oceans are so vast (nearly 72% of the earth's surface) that the moon's gravitational pull moves the water, resulting in high and low tides.

Coastal flooding from the ocean (not from direct rainfall) generally occurs in response to a combination of three processes which include:

• Abnormal high tide events — abnormal high tide events occur when the moon is either new or full and closest to Earth. These include  King Tides and Perigean Spring Tide .

• Storm Surge — the rise in seawater caused by a storm and associated winds.

• Persistent winds and waves — Flooding caused by offshore winds and repeated waves.

When combined, they worsen the effects on people living close to the coast. While coastal flooding is happening all over the world, some coastal communities are being impacted more than others.

The Center for Operational Oceanographic Products and Services (CO-OPS), a program office of the National Oceanic and Atmospheric Administration, has over 200 permanent long term coastal water level stations across the U.S that continuously monitor sea levels in real time.

They are an authoritative source for reliable and accurate data on water levels, currents, and other coastal oceanographic and meteorological information.

Sea level rise, caused by climate change and land-based ice melt, is increasing the volume of water in the ocean. NOAA works with other national agencies, state agencies, and universities to model sea level trends and project future rise around the world’s coastlines.

Based on this information they're able to show where the greatest changes in relative sea levels are occurring. On the map below, you'll notice the relative sea level trends in the eastern United States and locations in the South Pacific.

The data collected by NOAA provide insight into how the number of flooding days are changing over time.

Cities like Norfolk, Virginia, are experiencing increased occurrences of flooding at high tide. Scientists call these events nuisance floods or “sunny day flooding.” The number of these floods has doubled since the year 2000. While they may seem minor, they cause inconvenient road closures, storm drain issues, and degrade infrastructure.

For many coastal dwellers, it is obvious that the flooding events are happening more and more frequently. But the long-term data collected by NOAA provides conclusive evidence of what is causing this—sea level rise.

NOAA has predictive models to show how much sea level rise may occur in a specific area. They have six scenarios that differ based on how risk averse you are in your coastal management. This data is extremely valuable in assisting coastal communities in reducing their future vulnerability. 

Based on an intermediate risk averse model, NOAA predicts that by 2040 Norfolk Virginia will experience a sea level rise of approximately 1.3 feet.

Sea level rise may seem gradual and unpredictable, but the data shows us where it is happening now.

The Commonwealth of Virginia is proactively taking steps to manage and protect their vulnerable coastal regions. Using data provided by NOAA, they have modeled coastal flooding to identify infrastructure that will be particularly vulnerable in the future.

The Virginia coast has many low-lying areas that will look very different in the future given sea level rise projections. Let's see how this will impact the city of Norfolk.

Relative sea level rise is increasing. The uncertainty of resilience in Norfolk, VA communities is one shared by coastal communities across the globe. Without proper preparation, citizens face millions of dollars in infrastructure damage, community displacement, and property loss.

Luckily, we have data to support informed adaptation and coastal resilience. The more we collaborate, the wider the net of understanding is cast--ensuring community prosperity for generations to come

Use the resources below to see how coastal flooding will impact your community.

"The charts, maps, and visualizations in this story map provide snapshots of our current scientifically understood situation and give a peek into the future, which can be difficult to imagine. Yet, these complex challenges provide opportunities to discover solutions, tackle flooding, sustain environmental quality, and spur the growth of new jobs, careers, and communities that adapt and flourish." Dr. Tom Allen, Program Head for Sea Level Rise and Climate Science, Institute for Coastal Adaptation & Resilience (ODU)