At least 18 people have died, and hundreds of homes and businesses have been submerged after an atmospheric river brought days of catastrophic flooding to large parts of the South and Midwest, prompting comparisons to one of the most devastating weather disasters in U.S. history: the Great Flood of 1937.The atmospheric river, which the National Oceanic and Atmospheric Administration (NOAA) warned would bring extreme rainfall, unleashed deadly storms across Kentucky, Missouri, Arkansas and surrounding states.The ContextThe National Weather Service (NWS) described the situation as "catastrophic flooding" as rising waters swamped critical infrastructure and prompted evacuations across the region.While the death toll from the recent storms stands at 18 as of Sunday, according to the Associated Press, the scale of damage has revived historical memories of the Great Flood of 1937, which killed 385 people and left approximately one million homeless as the swollen Ohio River inundated cities from Pittsburgh to Cairo, Illinois.What To KnowThe 2025 atmospheric event has impacted a wider geographic area, but stronger modern flood control systems seem to have mitigated its deadliest potential."This is even more widespread than that," National Water Center Director Edward Clark told Newsweek when asked about the geographical area for the Great Flood of 1937. "But [the Great Flood of 1937] occurred before the construction of flood control systems like levees and dams."Clark told Newsweek on Friday that he couldn't speak to the integrity of dams as floodwaters rose."Anytime you put this amount of [pressure] on systems, this is the time where there is potential for infrastructure disruption," he said.As of Monday morning, a flood map from the National Water Center showed that 18 river gauges have documented a location that was in major flooding. There were 57 locations in moderate flooding and 178 locations in minor flooding.Clark said the Great Flood of 1937 was a "generational flood event" driven by up to 12 inches of rain that fell across Ohio. Clark said the more recent atmospheric river that dumped record rainfall across multiple states did not reach the level of the 1937 storm, but the system was more widespread than the one in 1937.Atmospheric River Kills 18Victims of the recent floods include a 57-year-old man in Missouri, a 5-year-old boy in Arkansas, and several others in Kentucky, where Mayor Craig Greenberg of Louisville warned the city was facing "one of the top 10 flooding events in Louisville history," according to Newsweek. Arkansas Governor Sarah Huckabee said the flooding affected multiple rivers across the state and noted that federal emergency aid would help "shore up property and roadways, and save lives."A flash flood emergency was declared across numerous counties, with NOAA flood stage maps warning that schools, hospitals, police stations and roadways could become submerged. Flash flood watches extended across the Southeast through Monday, with the NWS noting a heightened risk for damaging wind gusts and isolated tornadoes.So far, authorities have confirmed the following identities of the 18 reported: Gabriel Andrews, 9, was swept away by floodwaters while walking to his school bus stop in Frankfort, Kentucky. Matthew Terrell Collins Sr., 58, and his son, Matthew Terrell Collins Jr., 29, were killed when a tree fell on them during a storm at Bull Creek Golf Course in Midland, Georgia. Garry Moore, 68, chief of the Whitewater Fire Protection District in Missouri, died while assisting a stranded motorist. An unidentified 5-year-old boy, died after a tree fell on his family's home in Little Rock, Arkansas. An unidentified 74-year-old driver, died in Boston, Kentucky, due to storm-related incidents. Impacts From Both StormsThe 1937 flood, which began in mid-January of that year, resulted in historic rainfall and overwhelmed entire cities. Louisville was 70 percent underwater at its peak. According to the Encyclopedia of Arkansas, "385 people died, a million were left homeless, and property losses reached $500 million," equivalent to over $10 billion today. The flood permanently altered U.S. flood response strategies, eventually prompting the U.S. Army Corps of Engineers to construct major floodwalls and reservoirs across the Ohio River Valley.By comparison, the atmospheric river flooding that occurred over the weekend is estimated to have cost up to $90 billion in economic damage, AccuWeather reported.What People Are SayingNWS office in Louisville, Kentucky, in a flood warning: "Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles. Caution is urged when walking near riverbanks. Flooding is occurring or is imminent. Most flood related deaths occur in automobiles. Do not attempt to cross water covered bridges, dips, or low water crossings. Never try to cross a flowing stream, even a small one, on foot. To escape rising water find another route over higher ground."What Happens NextForecasters say the current flood threat will shift eastward into the southern mid-Atlantic region and Southeast at the start of the week. With floodwaters still rising in many towns and emergency crews deployed across multiple states, federal and state officials are continuing damage assessments and rescue operations.National Water Center service coordination hydrologist Jason Elliott previously told Newsweek that any flooding that occurred over the weekend could persist early into this week, as it takes time for waters to recede.