Dewees Island witnessed road flooding during the king tide this past Saturday through Tuesday. The front beach of Dewees Island also sustained significant beach erosion. Why did this happen? A series of weather events all lined up; rainfall associated with Sally, the predicted king tide, a strong East wind as well as a low pressure system associated with Hurricane Teddy offshore. Dewees Island did not sustain typical hurricane weather with strong winds and rain from Teddy, but the hurricane was near enough to contribute to offshore swell.
Hurricane Teddy has moved north, the East winds have laid down, no new recent rainfall, and we are moving to a waxing moon and a neap tide which will result in a lower high tide. The weather event the island experienced is a rare event for Dewees Island since there are only a few months of the year when hurricane season will align with a king tide and an East wind. The monitoring station on the Cooper River at the Charleston Harbor has indicated this event has produced the number 17th, 19th, 21st and 27th all time highest water levels for the Charleston Harbor.
The breach on the front beach has magnified the impact of the water levels during this event to areas along Pelican Flight Drive and Lake Timicau Lane as the un-managed high water within Lake Timicau finds its own outlets. The water control structures within Lake Timicau were designed to manage a controlled flow of water in and out of Lake Timicau restricted by the earthen berms (dikes). When the berms of Lake Timicau are fully functional to restrict the ocean high tides and regular king tide flooding the water levels and function of this managed impoundment would be comparable to what you see in the Impoundment.
King tides are predicted at the new moon for October 14-20, November 13-18 and December 13-16. If there is an East wind during these dates the tides will be magnified. If the wind is calm and there are no offshore tropical systems, this king tide event may go unnoticed by many people. The Island may also witness elevated tides associated with a full moon during the fall months if accompanied by an East wind or tropical system.
Thank you to everyone who submitted photos this last week of the high tide. Please continue to pass along photos of any high tide event that seems unique.
For more information please visit:
Detailed explanation on Tide Surges from NOAA – surge_intro
Historical Crests for Cooper River Charleston Harbor: Please note these levels include hurricanes (# 1-4 & 8), high tides and the 1,000-flood event (# 11 and 13) within the top 15 highest levels.