Soundside Impacts of a Northward Tracking Tropical Cyclone: Hurricane Emily (31AUG93), Cape Hatteras Area, North Carolina

Abstract

Hurricane Emily passed by Cape Hatteras, North Carolina as a Category 3 storm on August 31, 1993. The center of the eye stayed offshore; the western quadrants barely brushed land near the town of Buxton. Emily afforded a rare opportunity to observe the impacts of offshore-directed winds with enough fetch (across Pamlico Sound) to create large waves and significant storm surge along an estuarine shoreline. Surge elevations were amplified by the concavity of the soundside shoreline of the Cape Hatteras cuspate foreland. Soundside water levels were greater in magnitude than those at the open-ocean shoreline.

Emily caused no major oceanside dune breaching. Washovers were restricted to locations of recent previous dune breaches. A prominent feature of the post-storm landscape was a semicontinuous wrack line, up to I-meter thick, comprised primarily of salt marsh grass, mud, and other debris washed from Pamlico Sound onto Hatteras Island. Where water flow was not interrupted by dense vegetation and development, the wrack line was deposited on the backside of the single, continuous frontal dune ridge. The maximum elevation of the wrack line, which is a reasonable representation of storm surge, was 2.9 m.