North Carolina

King Tides Project

What is the King Tides Project?

The King Tides Project helps people all over the world understand how sea-level rise will impact their lives.

The King Tides Project is an international initiative, first started in Australia, to document extreme high tide events using photos. These photos can help us visualize how “normal” high tides could look in the future due to sea-level rise. From these images we can create a record of how our shoreline looks today and track future changes. By visualizing these higher tide events we can start to understand how rising sea-levels will impact local resources and community investments.

King Tide Project Map

What are king tides?

King Tides: a non-scientific term used to describe the predicted highest high-tide and lowest low-tide events of the year. King tides occur during a perigean (when Moon is closest to Earth) spring tide (full and new moon). In other words, a full or new moon must co-occur when the Moon is closest to Earth in its elliptical orbit. These condition cause extreme highs and lows during the daily tidal cycle. Due to their astronomical nature, king tides are regular and predictable events, reoccurring multiple times a year.

Amplified Tides: a non-scientific term to describe predicted higher and lower water level events that result when perigee and spring tides almost co-occur, yet are offset by a day or more.

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N.C. King Tides

For many of us living in coastal North Carolina, flooding is a normal part of life. The coast here is very flat, and tides, heavy rain events, and even wind play an important role in determining water levels.

The North Carolina coast experiences a wide range of tidal regimes. Water levels at a given location are influenced to varying degrees by both astronomical and meteorological forces and the relative contributions of these forces change over time.

Astronomical forcing is driven by the Earth’s position relative to its moon and the sun. Meteorological forcing is the summation of wind speed, direction, and duration, as well as atmospheric pressure. These forces shape the sea surface, which then interacts with the geomorphology of the coast, which together dictate patterns and levels of coastal inundation.

King tides are extremely high tide events that happen twice a year.

NOAA Water Level Stations

Variations in tidal amplitudes can be seen by examining observed water levels at different locations along the coast documented by the National Oceanographic and Atmospheric Administration (NOAA). Check out these water levels by following the links to the right!

Explore NOAA’s High Tide Flooding Viewer

Past Projects: Water Level Gauges

Beginning in 2017, the King Tides Project conducted a citizen science water level monitoring project across the NC coast with funding from North Carolina Sea Grant and Carolinas Integrated Sciences and Assessments. The NC King Tides team collaborated with the North Carolina Association of Floodplain managers, UNC-Chapel Hill Institute of Marine Sciences, and citizen scientists to gather spatially explicit water level data in order to better understand water level patterns at the local level.

Water levels can be difficult to predict because they vary significantly over time and spice due to a combination of drivers, from astronomical tides to wind. With a greater understanding of local patterns in water levels, officials and coastal zone managers can better plan for and build coastal resiliency, especially as high water-level events become increasingly common and coastal areas experience more frequent nuisance flooding.