Gravity Wave Event - February 3-4, 2006

High winds impacted much of the Charleston Harbor and surrounding communities between 1130 pm and 130 am, 3-4 February 2006. Numerous reports of high winds and wind damage were reported to forecasters at the National Weather Service in Charleston during this time. Preliminary indications are that the damaging winds were caused by the passage of a very strong gravity wave that moved through the Charleston area between 11 pm and midnight. The gravity wave appeared to have been generated by a large cluster of severe thunderstorms that impacted much of northeast Florida and far southeast Georgia late Friday evening. As the gravity wave approached, surface pressures dropped between 4 and 6 millibars in less than an hour; then began to quickly rise as strong downward motion developed after the passage of the wave. This strong sinking motion likely resulted in the mixing of much higher winds aloft down to the surface. The open, nearly frictionless fetch of the Charleston Harbor likely enhanced these winds which resulted in considerable wind damage. The most severe damage occurred at the Charleston City Marina which is located on the Ashley River on the southwest side of downtown Charleston. At this point, high winds in excess of 75 mph produced significant wave action on the exposed region of the Charleston Harbor where the Harbor meets the lower reaches of the Ashley and Stono Rivers. The combination of high winds and significant wave action damaged between 20 and 30 sailboats and yachts. A 40-50 ft sailboat sank when large waves pushed the boat onto the concrete dock and severely cracked its hull. The estimated value of the sunken vessel is $200,000 - $300,000 based on interviews with local mariners. One boat owner also had his hand severely injured while trying to secure his boat during the high winds.