Louisiana Underwater: The Impact of Extreme Rainfall

Written by Artie Johnson

Louisiana is one of the most vulnerable states in the United States to extreme rainfall. Its warm, humid climate allows the atmosphere to hold large amounts of moisture, while tropical storms, hurricanes, and slow-moving weather systems can produce enormous amounts of rain in a short period of time. In cities such as New Orleans, the problem is made worse by low-lying land and extensive development. When rainfall arrives faster than drainage pumps, canals, and streets can handle it, water can quickly accumulate and cause severe urban flooding. The City of New Orleans has documented dozens of significant flooding events since the late 1990s, demonstrating that extreme rainfall is an ongoing hazard rather than an isolated problem.

One of the clearest examples was the 2016 Louisiana floods. In August 2016, a slow-moving low-pressure system combined with an unusually moist tropical atmosphere and remained over southern Louisiana for several days. Between August 11 and 13, some areas received 20 to 30 inches of rain. Livingston recorded about 25.5 inches, while Watson received approximately 31.39 inches. Baton Rouge received more than 19 inches during the event. The extraordinary rainfall caused widespread flash flooding followed by river flooding across several watersheds. More than 30,000 people were rescued, and tens of thousands of homes and other structures were damaged. NOAA classifies the event as one of the most damaging U.S. flood disasters of its time.

The 2016 flood also demonstrated how extreme rainfall can overwhelm both natural and human systems. Rivers such as the Amite, Comite, Tickfaw, Natalbany, and Tangipahoa reached record levels. Major highways, including Interstates 10 and 12, were closed for days, while homes and businesses throughout the Baton Rouge region were flooded. The disaster was especially significant because the flooding did not come from a major hurricane. Instead, a combination of atmospheric moisture and a slow-moving weather system produced rainfall on a scale normally considered extremely rare.

Hurricane Ida in 2021 provides another important example of extreme rainfall and flooding in Louisiana. Ida made landfall in Lafourche Parish on August 29, 2021, as a powerful Category 4 hurricane with maximum sustained winds of 150 mph. NNational Ocean Service Although Ida is remembered particularly for its destructive winds, storm surge, and widespread power outages, its rainfall also contributed to flooding across southeastern Louisiana. Parts of New Orleans lost power for nearly a week as the hurricane caused extensive damage to infrastructure. Ida demonstrated that rainfall hazards can occur alongside other hurricane hazards, creating a much more complicated emergency for communities.

Extreme rainfall is also a recurring problem in New Orleans itself. Because much of the city is low-lying and heavily urbanized, rainfall must be rapidly collected and removed through drainage infrastructure. When rainfall falls faster than the system can process it, streets can flood even without a hurricane or major river overflowing. For example, on August 5, 2017, thunderstorms repeatedly developed over the New Orleans area and produced roughly 4 to 9 inches of rain within three to five hours. The rainfall overwhelmed the drainage system and caused widespread, deep street flooding. City reports recorded isolated amounts of 8 to 10 inches in only three to four hours, with some neighborhoods experiencing rainfall statistically comparable to a 100-year event.

Another major New Orleans rainfall event occurred in July 2019, when heavy rain associated with the developing Tropical Storm Barry affected the city. A Sewerage and Water Board gauge in the Tremé neighborhood recorded almost 8.4 inches, while a gauge in the Lower Ninth Ward recorded more than 9 inches, much of it falling within approximately three hours. The flooding resulted in road closures, vehicle damage, and hundreds of flood-insurance claims. These events illustrate an important point: New Orleans does not need to experience a direct hurricane strike to face serious flooding.

The extreme rainfall events of 2023 further showed that heavy precipitation remains a persistent threat. New Orleans recorded flash-flood events on May 9, July 22, and September 4, while the city's hazard-mitigation report also noted two heavy-rain events during the early winter that were not included in its main event database. These events occurred during a year that also brought periods of intense heat and drought, demonstrating that Louisiana can shift rapidly between very dry and extremely wet conditions. The repeated occurrence of heavy rainfall shows why flood preparation cannot focus only on hurricanes.

The effects of extreme rainfall in Louisiana are influenced by more than just the amount of rain that falls. Rainfall intensity, duration, soil conditions, drainage capacity, and land elevation all determine how much flooding occurs. In New Orleans, the combination of low elevation and extensive paved surfaces means that rainwater has relatively few places to naturally soak into the ground. Roads, buildings, and other impervious surfaces increase runoff, sending large quantities of water into the city's drainage network. If rainfall exceeds the system's capacity, water can accumulate quickly in streets and neighborhoods.

Extreme rainfall also creates economic and social consequences. Floodwater can damage houses, vehicles, businesses, roads, electrical infrastructure, and public facilities. Residents may be unable to reach work, school, hospitals, or other essential services. Repeated flooding can also increase insurance costs and make recovery more difficult for households that have already experienced previous disasters. The 2016 Louisiana flood, for example, caused tens of thousands of structures to be damaged or destroyed, while the 2017 and 2019 New Orleans rainfall events demonstrated how even a few hours of intense precipitation can disrupt a major city.

Overall, Louisiana's history of extreme rainfall shows that flooding is not limited to hurricanes or coastal storms. The 2016 floods, Hurricane Ida in 2021, the repeated heavy-rain events of 2023, and major New Orleans rainfall events all demonstrate different ways in which large amounts of water can threaten communities. Preparing for these events requires reliable drainage and pumping systems, accurate weather forecasting, flood warnings, resilient infrastructure, and individual preparedness. As extreme rainfall continues to pose a serious challenge, Louisiana communities—particularly low-lying areas such as New Orleans—must continue improving their ability to manage water before, during, and after major storms.

National Centers for Environmental Information. “Louisiana.” Billion-Dollar Weather and Climate Disasters, National Oceanic and Atmospheric Administration, www.ncei.noaa.gov/access/billions/state-summary/LA. Accessed 4 Sept. 2026.

National Ocean Service. “Hurricane Ida.” National Oceanic and Atmospheric Administration, 2021, oceanservice.noaa.gov/annualreport/2021/hurricane-ida.html. Accessed 4 Sept. 2026.

National Weather Service. “August 2016 Flood.” National Weather Service, weather.gov/lix/August2016flood. Accessed 4 Sept. 2026.

New Orleans Office of Homeland Security and Emergency Preparedness. “Orleans Parish 2023 Hazard Mitigation Annual Report.” City of New Orleans, 2023, nola.gov/nola/media/Homeland-Security/Files/Hazard-Mitigation/Orleans-Parish-2023-HM-Annual-Report.pdf. Accessed 4 Sept. 2026.

New Orleans Office of Homeland Security and Emergency Preparedness. “Flooding.” ReadyNOLA, City of New Orleans, ready.nola.gov/hazard-mitigation/hazards/flooding/. Accessed 4 Sept. 2026.

New Orleans Office of Homeland Security and Emergency Preparedness. “Updated: City Makes Additional Reminders Following August 5 Flooding.” ReadyNOLA, City of New Orleans, ready.nola.gov/incident/august-flood/updated-city-makes-additional-reminders-following/. Accessed 4 Sept. 2026.

Image: “Rain in New Orleans.” Artist and date unknown.