Why New Orleans Gets Hit By Hurricanes

The land on which New Orleans is built has origins that began about 5,000 years ago. As sea level was rising after the last glacial maximum, a series of barrier islands was built outward from the coast of Mississippi across what is now the southeastern edge of Lake Pontchartrain (Figure 2). These islands, called the Pine Islands were composed mainly of sand whose source was the Pearl River along the Mississippi – Louisiana border. At the time the Mississippi River was building its delta out toward the southeast of New Orleans building the Maringouin and Teche lobes of the delta complex (Figure 3). Beginning about 4,300 years ago the Mississippi River began to build the St. Bernard Delta lobe out toward the east. This lobe eventually intersected the Pine Island Barrier Island complex, eventually burying the sands, cutting off the drainage from the north to form Lake Pontchartrain, and building the land on which New Orleans would later be built.