Numerical modelling and computer visualization of the storm surge in and around the Croatan-Albemarle-Pamlico estuary system produced by hurricane Emily of August 1993

Abstract

Hurricane Emily unleashed its fury on the Outer Banks of North Carolina on 31 August 1993. Storm surge was a major cause of damage along the Outer Banks. The highest flood water (11-11.5ft) occurred in the Buxton area near Cape Hatteras, North Carolina. It was reported that this flood water was from storm surges along the sound side of the barrier islands. An experimental forecast was conducted for this event in real time using Croatan-Albemarle-Pamlico estuary systems (CAPES) storm surge prediction model developed at North Carolina State University (NCSU). It uses as input parameters the projected hurricane track, minimum center pressure, maximum sustained wind speed and radius of maximum wind speed provided by the National Hurricane Center (NHC). The forcing of the model also includes fresh water input from sound system rivers, and of coastal waters intruding into the sound via Ocracoke, Hatteras and Oregon inlets. The predicted maximum surge along the sound side of the Outer Banks was within 85-90% of the post-storm highwater-mark survey data provided by the U.S. Geological Survey (USGS). Albeit, an after the fact simulation using the post-storm analysis of the track of Emily provided by the NHC, the maximum storm surge along the sound side of the Outer Bancks predicted by the model was within 95-98% of the maximum highwater mark data. The location of the predicted maximum surge for both pre and first model runs was near Cape Hatteras, which agreed well with USGS's survey data. We conclude that the CAPES storm surge model is capable of providing accurate storm surge forecasts in and around the CAPES, but such forecasts are sensitive to not only the observed storm size and intensity but in particular, the projected storm track.