South Carolina Department of Health and Environmental Control (DHEC) is leading the South Carolina King Tides initiative to document the effect that extreme tide events have on our state’s beaches, coastal waterways, private property and public infrastructure.
What is a King Tide?
The term “King Tide” is a non-scientific term used to describe the highest seasonal tides that occur each year. In Charleston, the average high tide is about 5.5 feet above mean lower low water (MLLW). During a King Tide, water levels may reach 7 feet (above MLLW), or higher. These extreme tides typically occur when a spring tide (when the sun, moon, and earth align during a new and full moon, increasing tide ranges) takes place when the moon is closest to Earth during the 28-day elliptical orbit (known as a perigee). This is scientifically referred to as a perigean spring tide.
DHEC issues King Tide notifications to MyCoast members when water levels are predicted to reach 6.6 feet above MLLW or higher at Charleston Harbor Tide Station. Tide predictions, provided by the National Oceanic and Atmospheric Administration (NOAA), are based on the astronomical tide calendar, which takes into account the gravitational pull of the moon and sun on Earth’s oceans. Water levels may, however, exceed predicted heights due to meteorological conditions such as precipitation, onshore winds, or low atmospheric pressure.
The effect of individual King Tides may vary considerably. King Tides may result in coastal erosion, flooding of low-lying areas, and road closures which may disrupt normal daily routines. This is particularly true when a King Tide coincides with significant precipitation because water drainage and runoff is impeded.
Flooding that takes place during a King Tide is often referred to as nuisance flooding. Nuisance flooding is the water level above the minor flooding threshold set locally by the National Weather Service. In Charleston Harbor, this threshold is 7 feet above MLLW.
Over time, the frequency of nuisance flooding is expected to increase due to gradual mean sea level rise. According to NOAA, nuisance flooding has increased on all three U.S. coasts, between 300 and 925 percent since the 1960s. In Charleston, the average number of nuisance flood days from 1957 to 1963 was 4.6 days. The average number from 2007 to 2013 was 23.3 days, which is a 409 percent increase. By 2020, NOAA projects Charleston will see over 30 days of nuisance flooding annually. For additional information on the frequency of tidal flooding, see our Reference Page.
DHEC Needs Your Help
DHEC needs your help to capture photographs of King Tide events. DHEC will evaluate your photographs and include them in its long-term analysis of coastal vulnerability and planning initiatives with municipalities. DHEC may also use your photographs in presentations, publications, and on its website.
2017 Predicted King Tides
- April 26-29
- May 24-28
- June 22-25
- July 21-24
- August 19-21
- September 18
- October 7-9
- November 3-8
- December 2-6
(Detailed tide tables here.)
Recaps from Past King Tides (with Photos)
- SC King Tide Recap: April 2017
- SC King Tide Recap: December 2016
- SC King Tide Recap: November 2016
- SC King Tide Recap: October 2016
- SC King Tide Recap: September 2016
- SC King Tide Recap: July 2016
- SC King Tide Recap: June 2016
- SC King Tide Recap: May 2016
- SC King Tide Recap: April 2016
- SC King Tide Recap: November 2015
- SC King Tide Recap: October-November 2015
- SC King Tide Recap: September-October 2015
- SC King Tide Recap: August-September 2015
- SC King Tide Recap: July-August 2015
- SC King Tide Recap: May 2015
- SC King Tide Recap: April 2015
- SC King Tide Recap: March 2015
- SC King Tide Recap: October 2014
- SC King Tide Recap: September 2014
- SC King Tide Recap: August 2014
- SC King Tide Recap: July 2014
- SC King Tide Recap: January 2014
Selected King Tide Photos
Tips for Effective King Tides Photos
- Take pictures at or near peak high tide.
- Take pictures where the impact of the tide can be gauged against familiar landmarks like buildings, roads, sidewalks, parking lots, jetties, bridges, sea walls, shorelines, or bulkheads.
- Taking contrasting shots of peak high and peak low tides helps to show the tidal variability.
- Be Safe! Use good judgment when you are taking your photos. Stay away from dangerous situations particularly in stormy conditions and avoid taking risks.
For more information on the South Carolina King Tides Initiative, please contact Liz Hartje: Coastal Projects Manager.