Grand Isle has been repeatedly pummeled by
hurricanes throughout its history. On average, the town and barrier island of Grand Isle has been affected by tropical storms or hurricanes every 2.68 years (since 1877), with direct hits on average every 7.88 years. Some of the more severe are listed here. In 1860, a storm surge and great winds resulted in the total devastation of the island. In the
1893 Atlantic hurricane season Grand Isle was devastated by a storm surge. In the
1909 Atlantic hurricane season the island was hit with a second storm surge. A category 4 hurricane devastated Grand Isle on September 29 during the
1915 Atlantic hurricane season. Grand Isle was hit by a storm surge on August 22 during the
1947 Atlantic hurricane season. In 1956,
Hurricane Flossy damaged the island.
Hurricane Betsy in September 1965 and
Tropical Storm Frances in 1998 put the entire island under water. On September 26, 2002, Grand Isle was hit by
Hurricane Isidore, soon followed by
Hurricane Lili passing to the west of the island, causing significant damage.
Hurricane Cindy made a direct hit on Grand Isle on July 5, 2005. Even though damage was essentially limited to power outages and
beach erosion, the storm's strength still caught residents by surprise. in September 2005 in September 2008 at a beach in Grand Isle in May 2010
Hurricane Katrina pounded Grand Isle for two days, August 28–29, 2005, destroying or damaging homes and camps along the entire island. Katrina's surge reached at Grand Isle. Large waves severely damaged the only bridge linking Grand Isle to the mainland. A news report published less than two days after the hurricane hit falsely noted, however, that the area had been completely destroyed, reporting a scene similar to that which befell
Last Island in 1856. Less than a month later, Grand Isle was further affected by
Hurricane Rita. By mid October, a number of businesses were again open on the island.
Hurricane Gustav reached shore west of the island on September 1, 2008, at 9 am
CDT, and hit it with a measured wind speed of . It was one of the few locations in Louisiana affected while the storm was still classified as a major hurricane. While both storms' eyes passed the island at similar distances, Katrina's eastern passing caused the greatest damage on the bay side. The Gustav surge that washed over the island caused less damage than Katrina, in part due to the most vulnerable structures having already been destroyed by Katrina. Current construction codes prevented the rebuilding of such vulnerable structures. Barataria Pass water levels peaked at above recent high tide. Homes along
Louisiana Highway 1 had of water below them. Large sections of levee/dunes were washed onto the highway.
Hurricane Ike passed far south of the island on September 11, 2008, while crews worked to restore power and repair the levee/dune damage caused by Gustav. Some sections of LA 1 west of the island were covered by of water. Wind gusts reached and Barataria Pass water levels reached above recent high tide while Ike was away.
Hurricane Ida's eastern eye wall hit the area on August 29, 2021, on the 16th anniversary of Hurricane Katrina, causing widespread damage. It was reported that 100 percent of Grand Isle's structures were damaged, and around 40–50 percent of structures were completely destroyed. Nearly all of the town's
utility poles had either bent or collapsed from the extreme winds.
Entergy decided to fully rebuild and strengthen the island's power grid instead of repairing it like most communities north of Grand Isle had received.
Restoration In 1998, the state of Louisiana and its federal and local partners approved a coastal restoration project called Coast 2050: Toward a Sustainable Coast. It is a $14 billion fund that is hoped to be allocated over 50 years in around 77 restoration projects with the aim of creating a sustainable ecosystem of coastal Louisiana. While the plan focuses on all of Louisiana, restoration of the Barataria Basin was the first priority and Grand Isle is at the mouth of
Barataria Bay.
U.S. Congress had not approved the Coast 2050 plan, and when Hurricane Katrina and Hurricane Rita hit, the federal government was studying a less costly, scaled down proposal which could be initiated in the span of a decade. It is estimated that the project will cost $28 million and be completed by August 2009. The money will help Grand Isle strengthen its natural defenses, provide better hurricane protection, while also preserving a critical barrier island that buffers inland parishes from the full force of hurricanes. The Nature Conservancy hope that these oysters colonize on breakwater structures and that the space on these breakwater structures increase biodiversity. In response the
Deepwater Horizon Oil Spill, the Coalition and the National Wildlife Foundation organized the planting of more than 1,600 mangroves in
Grand Isle State Park on June 25, 2011. They hope that this planting will help stabilize the sediment and sand and provide habitat for wildlife, specifically
pelicans. It was the first project undertaken in Grand Isle since Hurricane Issac made landfall. Volunteers installed dune fences and planted more than 12,000 plugs of dune grass. This will help stabilize the fragile beach along Grand Isle. Abita Beer and CRCL together implemented this and other restoration projects which will directly restore dune habitat and strengthen Grand Isle State Park and other sites in the future. ==Geography==