The Chandeleur Islands are not ordinary barrier islands pushed up by ocean currents. They are the remnants of the St. Bernard Lobe, an ancient distributary of the Mississippi River delta that built these sandy ridges more than 2,000 years ago. When the Mississippi shifted its main channel westward, the lobe was abandoned, and the islands became orphans -- cut off from the river sediment that had created them and left to the mercy of the Gulf. They form the easternmost point of Louisiana, a chain of uninhabited sand stretching roughly north to south, separating the Chandeleur Sound from the open Gulf of Mexico. Today, they are part of the Breton National Wildlife Refuge, established in 1904 and the second-oldest refuge in the entire National Wildlife Refuge System.

For mariners and pilots crossing the Gulf, the Chandeleur Island Light was the landmark that confirmed their position. Built in 1895, the lighthouse stood watch over the islands for more than a century, surviving the hurricane that destroyed the islands' fishing settlement in 1915 and countless lesser storms. But the sand beneath it would not hold. In 1998, Hurricane Georges scoured the islands so severely that the lighthouse ended up standing in open water, surrounded by nothing but Gulf. The barrier islands had barely begun to recover when Hurricane Katrina struck on August 29, 2005. The combined assault of Hurricane Dennis and Katrina that summer reduced the islands to shoals and submerged formations, and the Chandeleur Island Light toppled into the sea.

The numbers tell a story of accelerating loss. Before 1996, the seaward front of the Chandeleur Islands lost 20 to 30 feet of land per year, mostly replaced by new sand accumulating at the rear. From 1996 to 2004, the loss rate grew dramatically. A survey in the 1980s estimated the islands could persist for about three more centuries, but that forecast assumed a stability that hurricanes have since shattered. A 2006 study by geologists at the University of New Orleans found that the usual sand and sediment patterns that rebuilt the islands after storms had not been restored since Katrina reworked the area. Unprecedented landslides on the seabed toward the Gulf side now allow stronger waves to reach the islands. In 2014, marine geologists predicted the islands could be mostly submerged within decades due to sea level rise, isolation from Mississippi River delta sediment, and damaging storms -- though a decade later, the islands remain largely intact, defying the timeline if not the trend.

Despite their fragility, the Chandeleur Islands remain an ecological treasure. The Breton National Wildlife Refuge protects the entire chain, providing critical habitat for migratory birds moving south along the Gulf flyway. The islands' marshes and shallow waters shelter species that depend on the transition zone between land and sea. Brown pelicans, terns, and shorebirds nest on the sandy ridges, while the surrounding waters support fish and shellfish populations that sustain Gulf fisheries. The 2010 Deepwater Horizon oil spill added insult to injury, surrounding the islands with oil slicks visible in aerial photographs. Yet the birds return each season, the marsh grass holds what sand it can, and the islands persist -- diminished, battered, but still present on the map, still curving through the Gulf like the ghost of a river that moved on long ago.