By Dan Burger (Coastal Services Division Director) and Liz Hartje (Coastal Projects Manager)
The highest predicted King Tides of 2015 are quickly approaching! At Charleston Harbor, water levels are expected to reach 7 feet and higher above Mean Lower Low Water (MLLW) at the end of September and October. These extreme high tides are predicted to occur during the peak of the Atlantic Hurricane Season. NOAA’s tide predictions are based on the astronomical tide calendar, which takes into account the gravitational pull of the moon and sun on Earth’s oceans. Keep in mind that water levels can exceed predicted heights under various meteorological conditions like onshore winds, low atmospheric pressure, and precipitation. In 2014, observed King Tide water levels often surpassed astronomical predictions at Charleston Harbor. For instance, there were over 3.5 times more King Tide days than predicted. Cumulatively, water levels were 6.6 feet MLLW or higher for total of 201 hours, over 5 times longer than predicted. On average, observed King Tides were 0.6 feet higher than astronomical predictions, with a maximum observed difference of nearly 2 feet above predicted levels. King Tides peaked just below 7 feet, on average, and the highest observed water level reached 7.6 feet (August 9).
MyCoast: South Carolina
The MyCoast: South Carolina King Tides Reporting Tool is revealing what King Tides look like on the South Carolina coast and how these events affect infrastructure, mobility, and our shared natural resources. Over 180 photos were submitted by MyCoast members last year, see photos from select reports below. Visit http://mycoast.org/sc or download the MyCoast app and start photo-documenting these extreme tide events using your smartphone!
Here’s a list of dates, times, and predicted tidal heights for this coming September and October:
|Date||Predicted Height* (Time)|
|September 28||7.0 (8:29 a.m.)|
|September 29||7.1 (9:22 a.m.)|
|September 30||7.0 (10:16 a.m.)|
|October 26||7.0 (7:16 a.m.)|
|October 27||7.2 (8:10 a.m.)|
|October 28||7.2 (9:03 a.m.)|
|October 29||7.1 (9:55 a.m.)|
|* Feet above MLLW at Charleston Harbor Tide Station|