Barrier Island Breakdown: The Ephemeral Outer Banks of North Carolina

Abstract

This chapter describes sudden coastal change that took place in North Carolina, USA 1200 years ago during a period of warmth in the northern hemisphere known as the Medieval Climate Anomaly. It explains how we know that this event occurred, and it describes the geologic tools that we used to reconstruct the event. A large segment of the Outer Banks barrier islands was flattened, probably by one or more strong hurricanes. Oceanic waters entered estuarine Pamlico Sound, which metamorphosed into an open Pamlico Bay. The tidal range increased, tidal currents increased in strength, salinity increased, and fish migrated as they adapted to new conditions. Human inhabitants of the region would also have had no choice but to adapt. Over 500 years the barrier islands were reconstructed and pre-storm conditions returned by the time the first Europeans landed on this coast in 1585. A similar series of events could occur once more in coastal North Carolina during the current period of global warming. Economic effects would be disastrous.