Dauphin Island: A Dynamic Barrier Island
Dauphin Island, the easternmost barrier island along the Mississippi and Alabama coastlines, serves as a vital buffer against the relentless Gulf of Mexico waves. Stretching 14 miles in length, this island plays a significant role in protecting the mainland, while also providing a habitat for migratory birds.
Barrier islands like Dauphin Island are in a constant state of flux, shaped by the natural forces of currents and tides. In 2005, Hurricane Katrina caused significant damage to the island, altering its western side. Fast forward to 2023, and a new image captured by the Operational Land Imager-2 (OLI-2) on Landsat 9 reveals a sandy peninsula emerging on the eastern side of the island, a feature that did not exist two decades ago.
Renowned coastal engineer and emeritus professor Scott Douglass has been closely monitoring the changes on Dauphin Island. He observed the merging of Pelican Island with Dauphin Island in 2008, a phenomenon he had predicted almost a decade earlier based on tidal currents pushing sand towards the larger landmass.
The convergence of these two islands has not only reshaped the landscape but also benefited Dauphin Island by replenishing its eroding beaches. This natural process of island merging serves as a form of beach nourishment, a welcome development for the island’s conservation efforts.
As Douglass points out, the collision of barrier islands with Dauphin Island is not a new occurrence. Historical data dating back to the 18th century indicates that such events have taken place in the past, approximately every 150 years. This geological process, captured in real-time through satellite imagery, offers a rare glimpse of natural evolution in action.
The images of Dauphin Island’s transformation serve as a testament to the dynamic nature of our planet’s landscapes. As experts continue to monitor and study these changes, we gain a deeper understanding of the intricate processes that shape our coastal environments.
Photo Credit: NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Story by Emily Cassidy.