Louisiana is exceptionally susceptible to the destructive power of tropical cyclones, including hurricanes—rotating, organized systems of clouds and thunderstorms that form over tropical or subtropical waters, with sustained winds reaching 74 miles per hour or greater, categorized by the Saffir-Simpson Hurricane Wind Scale. The combination of its geographic position on the Gulf of Mexico and its low-lying elevation ensures the state is one of the most frequently impacted regions in the United States.
Frequency and Historical Precedent
The official hurricane season for the Atlantic basin, which includes the Gulf of Mexico, runs annually from June 1st through November 30th. Louisiana is second only to Florida in the number of tropical storms and hurricanes that have made landfall since 1851. On average, a tropical cyclone of at least tropical storm strength affects some part of the state approximately two out of every three years, with a hurricane making landfall roughly every 2.8 years.
The historical record illustrates the variety and severity of these storms, with major hurricanes often striking during the peak months of August through October. Hurricane Audrey in 1957 made landfall as a strong Category 3, demonstrating the destructive potential of early-season Gulf-originated storms. More recently, Hurricane Laura in 2020 tied the 1856 Last Island hurricane as the strongest storm by wind speed to ever hit the state, making landfall as a high-end Category 4.
Hurricane Ida in 2021 also made landfall as a high-end Category 4, causing immense damage across southeastern Louisiana. While Hurricane Katrina in 2005 was a Category 3 at Louisiana landfall, its enormous size and the subsequent catastrophic failure of the New Orleans levee system made it one of the most devastating and costly natural disasters in US history.
Unique Geographical Vulnerability
Louisiana’s unique geography is the primary factor driving its extreme hurricane risk, differentiating it from other coastal states. Much of the state’s southern half is characterized by extremely low elevation, with many areas lying at or even below sea level. This flat, low topography allows storm surge to push much farther inland than in states with steeper coastal plains.
The Mississippi River Delta further destabilizes the region, as the deltaic soils are subject to subsidence, meaning the land is naturally sinking and compacting. This geological process, combined with chronic coastal erosion, continually lowers the effective elevation of the coast. Barrier islands and coastal wetlands, which historically served as natural buffers to storm surge by absorbing wave energy, are disappearing at rapid rates.
The loss of these natural storm barriers means that tropical storm water and wind energy now reach inland communities with greater force. Human alterations, such as the construction of canals for navigation and oil exploration, have exacerbated wetland loss and provided pathways for storm surge to penetrate deeper into the interior.
Specific Regional Risk Profiles
Hurricane threats vary significantly across Louisiana, depending on the proximity to the coast and the local geography.
Coastal Parishes
Coastal Parishes like Terrebonne, Lafourche, and Cameron face the highest risk, primarily from storm surge and extreme wind damage. These low-lying areas are directly exposed to the Gulf of Mexico, making them the first to experience the full force of a hurricane’s wind field and the most dangerous aspect of the storm: the massive, advancing wall of water known as storm surge. The severity of the surge is amplified by the shallow offshore depths, which allow the water to pile up against the shoreline.
New Orleans Metropolitan Area
The New Orleans Metropolitan Area presents a unique and complex risk profile due to its bowl-like geography, with significant portions of the city lying below sea level. The city relies on a massive Hurricane Storm Damage Risk Reduction System (HSDRRS), a network of levees, floodwalls, and pumps, to protect against high water from Lake Pontchartrain and the Gulf. The primary threats here are storm surge from the surrounding water bodies and intense rainfall flooding, which requires the city’s drainage system to actively pump water out. Even with the strengthened system, the risk of inundation remains, especially from massive storm surges that could overtop the flood defenses.
Inland Areas
Inland Areas of central and northern Louisiana, such as those near Alexandria and Shreveport, are protected from ocean storm surge but face different hazards. The primary concern for these regions is extreme rainfall and prolonged flooding, as the slow movement of a tropical system can drop enormous amounts of water over a short period. These areas also experience high winds that can cause significant damage to trees and infrastructure, often maintaining the intensity of a tropical storm or Category 1 hurricane long after landfall. The flood risk inland is compounded by the potential for river flooding as heavy rain swells tributaries and channels.