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The Chandeleur Islands (french: Îles Chandeleur) are a chain of uninhabited
barrier island Barrier islands are coastal landforms and a type of dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a ...
s approximately long, located in the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...
, marking the outer boundary of the Chandeleur Sound. They form the easternmost point of the state of
Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is bord ...
, United States and are a part of the Breton National Wildlife Refuge. They are an important migrating point for many birds on their way south, and are a prime marsh and forest wildlife area.


History

The islands were formed over 2,000 years ago as the rim of the St. Bernard Lobe of the
Mississippi River The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...
delta. The islands were named when the explorer
Pierre Le Moyne d'Iberville Pierre Le Moyne d'Iberville (16 July 1661 – 9 July 1706) or Sieur d'Iberville was a French soldier, explorer, colonial administrator, and trader. He is noted for founding the colony of Louisiana in New France. He was born in Montreal to French ...
was sailing in search of the mouth of the Mississippi River along the Gulf Coast. He christened the islands on the eve of Fête de la Chandeleur—also known as Candlemas, a Christian feast day—on February 1, 1700. The Breton National Wildlife Refuge was established in 1904 and includes all of the Chandeleur Islands in the Gulf of Mexico. The refuge is the second-oldest in the National Wildlife Refuge System. Prior to destruction by a hurricane in 1915 there was a fishing settlement on the islands, and even earlier there had been farming on the islands. The Chandeleur Island Light, built in 1895, stood as a landmark and recognizable location for mariners at sea and pilots flying over the
Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...
. The islands were constantly eroded and changed by wave action, and most dramatically after the
storm surge A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the ...
s following
hurricane A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Dep ...
s. The islands have been generally shrinking and migrating landward since the late 19th century. A survey in the 1980s estimated that they would be in existence for about three more centuries. Before 1996, the seaward front of the islands lost about 20–30 feet of land each year, mostly replaced at the rear. From 1996 to 2004, the loss rate grew to about per year. In 1998,
Hurricane Georges Hurricane Georges () was a powerful and long-lived Cape Verde Category 4 hurricane which caused severe destruction as it traversed the Caribbean and Gulf of Mexico in September 1998, making eight landfalls along its path. Georges was the seventh ...
destroyed the islands and left the lighthouse in the middle of the ocean, and the
barrier island Barrier islands are coastal landforms and a type of dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a ...
s only just recovered when Hurricane Katrina struck on August 29, 2005. However, the combined effect of
Hurricane Dennis Hurricane Dennis was an early-forming major hurricane in the Caribbean and Gulf of Mexico during the record-breaking 2005 Atlantic hurricane season. Dennis was the fourth named storm, second hurricane, and first major hurricane of the season. F ...
and Hurricane Katrina in 2005 reduced the island to
shoals In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...
or sub-surface formations, and toppled the Chandeleur Island Light. Powerful storms can produce changes that would otherwise have taken many years. A study released in 2006 by
geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...
s from the University of New Orleans shows that the usual sand and sediment patterns that rebuilt the islands after big storms have not been restored since Katrina reworked the area. There is also evidence of unprecedented landslides on the seafloor on the side toward the Gulf of Mexico, potentially allowing stronger waves with greater erosional impact to reach the islands. Numerical models developed by other marine geologists indicate the islands could be mostly submerged within decades due to
sea level rise Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cr ...
, isolation from Mississippi River delta sediment, mud foundations, sediment transport issues, and damaging storms.


References


Further reading

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External links


Post-Ivan September 18, 2004 photo

Change in the Length of the Middle Section of the Chandeleur Islands Oil Berm, November 17, 2010, through September 6, 2011 - USGS

Change in the Length of the Northern Section of the Chandeleur Islands Oil Berm, September 5, 2010, through September 3, 2012 - USGS
{{authority control Barrier islands of Louisiana Landforms of Plaquemines Parish, Louisiana Landforms of St. Bernard Parish, Louisiana Deepwater Horizon oil spill Uninhabited islands of the United States