The Mississippi River is the primary river and second-longest river of the largest drainage basin in the United States. From its traditional source of Lake Itasca in northern Minnesota, it flows generally south for 2,340 miles (3,766 km) to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U.S. states and two Canadian provinces between the Rocky and Appalachian mountains. The main stem is entirely within the United States; the total drainage basin is 1,151,000 sq mi (2,980,000 km2), of which only about one percent is in Canada. The Mississippi ranks as the thirteenth-largest river by discharge in the world. The river either borders or passes through the states of Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.
The Great Flood of 1993 was a flood that occurred in the Midwestern United States, along the Mississippi and Missouri rivers and their tributaries, from April to October 1993.
Hurricane preparedness in New Orleans has been an issue since the city's early settlement because of its location.
A levee breach or levee failure is a situation where a levee fails or is intentionally breached, causing the previously contained water to flood the land behind the levee.
The Mid-Atlantic United States flood of 2006 was a significant flood that affected much of the Mid-Atlantic region of the eastern United States. The flooding was very widespread, affecting numerous rivers, lakes and communities from Upstate New York to North Carolina. It was widely considered to be the worst flooding in the region since Hurricane David in 1979. It was also one of the worst floodings in the United States since Hurricane Katrina in August 2005. At least 16 deaths were related to the flooding.
Floods in the United States are generally caused by excessive rainfall, excessive snowmelt, and dam failure. Below is a list of flood events that were of significant impact to the country during the 20th century, from 1900 through 1999, inclusive.
Floods in the United States (2000–present) is a list of flood events which were of significant impact to the country during the 21st century, since 2000. Floods are generally caused by excessive rainfall, excessive snowmelt, storm surge from hurricanes, and dam failure.
The 2007 Midwest flooding was a major flooding event that occurred in the Midwestern United States in the third week of August 2007. While Hurricane Dean was affecting the Yucatán Peninsula and the Gulf of Mexico, and Tropical Storm Erin was affecting Oklahoma and Texas, a persistent storm system hung over the Midwest for several days, causing repeated flash flooding in the US states of Illinois, Indiana, Iowa, Minnesota, Ohio, and Wisconsin. Cool Canadian air clashed with large quantities of warm moist air from the Gulf, producing torrential rains along a stationary front. 5 deaths across the central United States were attributed to the resulting flooding. Seven Minnesota counties, eight Ohio counties, fourteen counties in Wisconsin, and seven counties in Illinois were declared Federal Disaster Areas.
The March 2008 Midwest floods were a massive flooding event in the Southern Midwest and portions of the Southern Plains. Cape Girardeau, Missouri officially reported 11.48 inches (29.2 cm) between March 18 and 19. At least 17 people died as a result of the flooding. Levee breaks were observed in several areas, most notably in Southeastern Missouri, where levee breaks occurred through mid-April.
The June 2008 Midwestern United States floods were flooding events which affected portions of the Midwestern United States. After months of heavy precipitation, a number of rivers overflowed their banks for several weeks at a time and broke through levees at numerous locations. Flooding continued into July. States affected by the flooding included Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri and Wisconsin. The American Red Cross assisted the victims of flooding and tornadoes across seven states and the National Guard was mobilized to assist in disaster relief and evacuation.
The Iowa flood of 2008 was a hydrological event involving most of the rivers in eastern Iowa which began June 8 and continued until July 1. Flooding continued on the Upper Mississippi River in the southeastern area of the state for many more days. The phrase "Iowa's Katrina" was often heard.
The 2009 Red River flood along the Red River of the North in North Dakota and Minnesota in the United States and Manitoba in Canada brought record flood levels to the Fargo-Moorhead area. The flood was a result of saturated and frozen ground, spring snowmelt exacerbated by additional rain and snow storms, and virtually flat terrain. Communities along the Red River prepared for more than a week as the U.S. National Weather Service continuously updated the predictions for the city of Fargo, North Dakota, with an increasingly higher projected river crest. Originally predicted to reach a level of near 43 feet (13 m) at Fargo by March 29, the river in fact crested at 40.84 feet (12.45 m) at 12:15 a.m. March 28, and started a slow decline. The river continued to rise to the north as the crest moved downstream.
The US State of North Dakota experienced significant flooding in its major river basins in 2009, following abnormally heavy winter snows atop saturated and frozen ground.
Major floods along the Mississippi River in April and May 2011 were among the largest and most damaging recorded along the U.S. waterway in the past century, comparable in extent to the Great Mississippi Flood of 1927 and Great Flood of 1993. In April 2011, two large storm systems deposited record levels of rainfall on the Mississippi River drainage basin. When that additional water combined with the springtime snowmelt, the river and many of its tributaries began to swell to record levels by the beginning of May. Flooding occurred in Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.
The 2011 flooding event on the Missouri River in the United States was triggered by record snowfall in Rocky Mountains of Montana and Wyoming along with near-record spring rainfall in central and eastern Montana. All six major dams along the Missouri River released record amounts of water to prevent overflow which led to flooding threatening several towns and cities along the river from Montana to Missouri; in particular Bismarck, North Dakota; Pierre, South Dakota; Dakota Dunes, South Dakota; South Sioux City, Nebraska, Sioux City, Iowa; Omaha, Nebraska; Council Bluffs, Iowa; Saint Joseph, Missouri; Kansas City, Missouri; Jefferson City, Missouri, and St. Louis, Missouri. Many smaller towns were also at risk, suffering the same fate as the larger cities if not worse. According to the National Weather Service, in the second half of the month of May 2011, almost a year's worth of rain fell over the upper Missouri River basin. Extremely heavy rainfall in conjunction with an estimated 212 percent of normal snowpack in the Rocky Mountains contributed to this flooding event.
The 2011 Souris/Mouse River flood in Canada and the United States occurred in June and was greater than a hundred-year flooding event for the river. The US Army Corps of Engineers estimated the flood to have a recurrence interval of two to five centuries.
The 2013 Grand Rapids flood lasted from April 12 to 25, 2013, affecting multiple areas in the Grand Rapids metropolitan area. Sudden heavy rainfall, saturation of the ground from rainwater and the flow of tributaries caused the Grand River to rise dramatically, with the river cresting at 21.85 feet (6.66 m) in Grand Rapids on April 21, 2013. The flooding caused thousands of residents in the area to evacuate their homes.
The Midwestern United States experienced major floods in the spring of 2019, primarily along the Missouri River and its tributaries in Nebraska, Missouri, South Dakota, Iowa, and Kansas. The Mississippi River also saw flooding, although starting later and ending earlier. The 2019 January-to-May period was the wettest on record for the U.S., with multiple severe weather outbreaks through May in the Midwest, High Plains, and South exacerbating the flooding and causing additional damage. Throughout late May and early June, rain in Iowa, Illinois, and Missouri caused every site on the Mississippi River to record a top-five crest. At least three people in Iowa and Nebraska died.
Between May and June 2019, an extended sequence of heavy rainfall events over the South Central United States caused historic flooding along the Arkansas River and its tributaries. Major and record river flooding occurred primarily in northeastern Oklahoma, and the elevated flows continued downstream into Arkansas where they caused additional inundation. Antecedent soil moisture levels and water levels in lakes and streams were already high from previous rains, priming the region for significant runoff and flooding. The prolonged combination of high atmospheric moisture and a sustained weather pattern extending across the continental United States led to frequent high-yield rainfall over the Arkansas River watershed. The overarching weather pattern allowed moisture levels to quickly rebound after each sequential rainfall episode. With soils already saturated, the excess precipitation became surface runoff and flowed into the already elevated lakes and streams. Most rainfall occurred in connection with a series of repeated thunderstorms between May 19–21, which was then followed by additional rains that kept streams within flood stage.
A winter storm in March 2023 impacted much of the Western, Northern, and Northeastern United States, producing high snowfall totals and widespread damage across the region. The winter storm, unofficially named Winter Storm Sage by The Weather Channel, first progressed across the Western United States as an atmospheric river, and then moved across the northern United States, bringing blizzard conditions and moderate snowfall across the Northern U.S.. The winter storm then became a nor'easter and impacted the Northeast, bringing snowfall rates of 1–2 inches (2.5–5.1 cm) per hour across numerous locations across the Northeast and 3 feet (36 in) of snow in several locations across the region with locally higher amounts. More than 320,000 power outages occurred across the areas impacted by the winter storm, and caused three fatalities and two injuries. Readsboro, Vermont received 42.1 inches (107 cm) of snow, and nearly 200 car accidents occurred across the New England region in the Northeast.
