Hanna (2008)

A tropical wave that moved off Africa on 19 August developed into a tropical depression on 28 August about 275 nautical miles east-northeast of the northern Leeward Islands. It became Tropical Storm Hanna on 28 August and moved generally west-northwest and later southward and southwestward in response to changes in upper-level winds and nearby ridges. Hanna underwent a period of rapid strengthening around 1–2 September near the Caicos Islands, then weakened quickly due to increasing wind shear, executed a small counterclockwise loop near the Turks and Caicos and north of Hispaniola, moved northwestward past the central Bahamas, and accelerated northward along the U.S. East Coast before becoming extratropical over southern New England on 7 September.

Hanna made multiple close approaches and landfalls. It reached peak strength over Providenciales in the Caicos Islands around 0000 UTC 2 September, and passed very near Middle Caicos Island on 3 September. Its U.S. landfall occurred near the North Carolina–South Carolina border at about 0720 UTC 6 September as a strong tropical storm. The system’s center passed very close to New York City shortly after 0000 UTC 7 September before becoming extratropical over southern New England.

The storm’s maximum intensity was estimated at 75 knots (about 85 mph) with a minimum central pressure near 977 mb around 0000 UTC 2 September, making it a Category 1 hurricane at peak. That peak was brief; Hanna had weakened back to tropical-storm strength (about 60 knots) by the time it reached the U.S. coast and had weakened further after landfall.

Storm surge and rainfall produced notable local impacts. Measured storm surge and storm-tide values included about 7.25 ft storm tide at Springmaid Pier, South Carolina (with a 3.50 ft surge) and storm tides of about 6–7 ft at several sites along southeastern North Carolina (for example Ocean Isle Beach ~7.00 ft storm tide). Heavy rain affected Hispaniola and Puerto Rico especially: Puerto Rico had a maximum reported total of 16.19 inches near Adjuntas; Oviedo in the Dominican Republic reported 14.17 inches; Camp Perrin, Haiti reported 12.72 inches. Over the U.S. mid-Atlantic and Northeast, rainfall totals reached as high as 9.65 inches at Woodbridge, Virginia, with widespread 3–7 inch amounts in many coastal and inland areas.

Casualties and damage were most severe in Haiti where heavy rains and flooding associated with Hanna — compounded by earlier storms — were linked to a very large number of fatalities. Reports cited roughly 500 deaths in Gonaives and an overall high death toll in Haiti tied to the sequence of storms; final attribution among the storms remained uncertain. In the Bahamas and Turks and Caicos damages were generally minor (roof and road damage, boats washed ashore) and no casualties were reported there. In the United States Hanna produced about $160 million (estimated total damages), widespread power outages, downed trees and some coastal flooding and beach erosion in the Carolinas; one indirect U.S. death (a drowning in Georgetown County, South Carolina) was reported.

Noteworthy aspects include Hanna’s rapid but short-lived intensification to a Category 1 hurricane over the Caicos Islands and its abrupt weakening soon after due to northerly wind shear. Forecasts had difficulty with Hanna’s unexpected southward turn and small cyclonic loop near the Turks and Caicos on 2–3 September; official track errors were larger than long-term averages through 72 hours, and many forecasts did not predict the brief hurricane peak. Warnings and watches were issued for large portions of the Bahamas, Hispaniola, and a long stretch of the U.S. East Coast with lead times of roughly 34–46 hours for the main U.S. tropical-storm and hurricane alerts.