April 1, 2024 | Allison Robertson

The Worst Floods in U.S. History


Flooding in America

Over the past 50 years, America has experienced a 20% increase in heavy rainfall, as a result of global climate change.

We’ve also seen a huge increase in hurricanes—which most often cause flooding.

flood split image

Types of Floods: Coastal Floods

There are three main types of floods. The type is coastal.

Also known as storm surges, these typically occur when a high tide coincides with an intense storm, like a tsunami or hurricane, forcing large amount of water onshore.

Coastal Flooding At Outer BanksNorth Carolina Department of Transportation, CC BY 2.0, Wikimedia Commons

Types of Floods: River Floods

Also known fluvial floods, these occur when the water level of a lake or river overflows onto surrounding lands. These are usually caused by intent rainfall or snowmelt.

River FloodsWater Alternatives Photos, Flickr

Types of Floods: Flash Floods

Also known as pluvial floods, these occur when extreme precipitation causes a flood independent of a body of water. These can happen anywhere, including urban areas when the drainage system or dam is overwhelmed.

Flash Flooding In A City StreetCMBJ, CC BY-SA 3.0, Wikimedia Commons

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The Worst Kind of Flood in America

The worst kind of floods that affect America the most are coastal floods—primarily due to hurricanes and tropical storms.

Coastal floodingBruno Sanchez-Andrade Nuño, Flickr

Deadliest Natural Disaster in America

Topping the charts is The Galveston Storm of 1900—which is considered the deadliest natural disaster in U.S. history, with a disturbing loss of over 8,000 people.

1900 Galveston hurricanepingnews.com, Flickr

Second Deadliest Flood

Next on the list for deadliest natural disasters, in terms of flooding, is The Great Flood of 1862, which caused upwards of 4,000 fatalities.

Here is a list of some of the worst floods to devastate the United States.

Great Flood of 1862Unknown Author, Wikimedia Commons

Central Valley, California, 1862

Date: December 1861-January 1862
Cause: Record-high rainfall and snowmelt

Also called The Great Flood of 1862, it was the largest flood in the recorded history of California, Oregon, and Nevada, inundating the western United States and portions of British Columbia and Mexico.

Great Flood of 1862Drouaillet, Wikimedia Commons

Central Valley Flood, California

The flood caused at least 4,000 fatalities in California alone, and property damages estimated over $3 billion, which was massive for its time.

The sheer cost made this event known as “the storm that caused California to go bankrupt.”

Montgomery Block, 1862George Robinson Fardon, Wikimedia Commons

Johnstown, Pennsylvania, 1889

Date: May 31, 1889
Cause: Failure of the South Fork Dam after heavy rainfall

The Johnstown Flood included a 30-foot wall of water surging toward the town at speeds of 40mph, resulting in more than 2,200 fatalities.

Johnstown FloodE. Benjamin Andrews, Wikimedia Commons

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Johnstown, Pennsylvania

Countless other people suffered serious injuries and hundreds of people were left homeless. Property damages were estimated at over $600 million.

The Johnstown Flood of 1889Francis Schell and Thomas Hogan, Wikimedia Commons

Sea Islands Hurricane, 1893

Date: August, 1893
Cause: Hurricane

The Sea Islands Flood was the devastating result of Sea Islands Hurricane, which at the time was the 7th deadliest hurricane in U.S. history.

Rock Island floodLibrary of Congress, Picryl

Sea Islands Hurricane

The flood took the lives of 2,000 people and left thousands more homeless.

Property damages were estimated at $23 million and took over 10 months to rebuild.

1893 sea islands hurricaneUnknown Author, Wikimedia Commons

San Ciriaco Hurricane, 1899

Date: August-September, 1899
Cause: Category 4 Hurricane

The San Ciriaco hurricane was the longest-lived Atlantic hurricane on record, and the third-longest-lived tropical cyclone globally on record—lasting 4 weeks in total.

1899 San Ciriaco hurricaneNorth Carolina Division of Archives and History, Wikimedia Commons

San Ciriaco Hurricane

The hurricane was also one of the deadliest Atlantic hurricanes in recorded history, with an estimated 3,800 fatalities.

San Ciriaco Hurricane of 1899Unknown Author, Wikimedia Commons

San Ciriaco Hurricane

The hurricane hit Leeward Islands, Puerto Rico, Hispaniola, Turks and Caicos Islands, Cuba, Bahamas, East Coast of the United States, and Atlantic Canada—causing serious flooding on many of the island nations.

Property damage was estimated at over $74 million.

Puerto Rico And Its Resources (1899)Frederick Albion Ober, Wikimedia Commons

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Galveston, Texas, 1900

Date: Sept. 8, 1900
Cause: Category-4 Hurricane

The Galveston Flood, also referred to as the Galveston Hurricane of 1900, is the deadliest natural disaster in United States history, with 8,000 fatalities, and one-third of the population homeless.

Galveston Hurricane of 1900Unknown author, Wikimedia Commons

Galveston, Texas

The hurricane left the coastline under 12 feet of water, and property damages were estimated at $1.25 billion.

Galveston Hurricane, 1900Library of Congress, Wikimedia Commons

Mississippi River, 1927

Date: April-May 1927
Cause: Levee system overpowered by heavy rainfall

This flood is known as the most destructive river flood in the history of the United States.

Mississippi River floodNational Archives and Records Administration, Wikimedia Commons

Mississippi River

Over 500 people lost their lives and 600,000 people were left homeless.

More than 23,000 square miles of land was submerged.

Great Mississippi Flood of 1927National Archives and Records Administration, Wikimedia Commons

Lake Okeechobee Flood, 1928

Date: September, 1928
Cause: Hurricane

The Lake Okeechobee Hurricane was one of the deadliest hurricanes in the recorded history of the North Atlantic basin, and the fourth deadliest hurricane in the United States.

1928 Okeechobee hurricaneRoy Senff, Wikimedia Commons

Lake Okeechobee Flood

Torrential rainfall overwhelmed the dam holding back the water of Lake Okeechobee and flooded hundreds of square miles to depths more than 20 feet, taking the lives of over 2,500 people.

Property damages were estimated at over $25 million.

1928 Okeechobee hurricaneRoy Senff, Wikimedia Commons

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Ohio River, 1937

Date: January-February 1937
Cause: Heavy rainfall

This flood remains the flood of record for many locations along the Ohio River, with 385 fatalities and over a million people left homeless.

Ohio River flood of 1937Huntington District, Wikimedia Commons

Ohio River Flood

Damage stretched from Pittsburgh, Pennsylvania, to Cairo, Illinois. Federal and state resources were strained to aid recovery as the disaster occurred during the depths of the Great Depression.

Property damages reached over $10 billion.

Ohio River flood of 1937Russell Lee, Wikimedia Commons

Hurricane Camille, 1969

Date: August 1969
Cause: Category-5 Hurricane

Hurricane Camille became the second most intense tropical cyclone on record to strike the United States, with more than 260 fatalities and tremendous damage.

Hurricane Camille, 1969Coast and Geodetic Survey, Wikimedia Commons

Hurricane Camille

Camille caused tremendous damage in its wake and produced a peak official storm surge of 24 feet. It flattened nearly everything along the Mississippi coast.

Property damages are estimated at over $12 billion.

Hurricane Camille, 1969NOAA Photo Library, Flickr

Rapid City, South Dakota, 1972

Date: June 9-10, 1972
Cause: Rapid rainfall caused rivers to overflow

Also known as the Black Hills Flood of 1972, this flash flood was the most detrimental flood in South Dakota history, and one of the deadliest floods in U.S. history.

Johnstown floodVCU Capital News Service, Flickr

Rapid City, South Dakota

The flood resulted in 238 fatalities and 3,057 injuries, and left thousands of people homeless. Property damage was estimated at over $2 billion.

Rapid City floodNOAA, Wikimedia Commons

Big Thompson Canyon, Colorado, 1976

Date: July 31, 1976
Cause: A stalled thunderstorm inundated the river with water at rapid speeds

This flash flood is considered one of the deadliest floods in the history of Colorado, causing at least 144 fatalities and 250 injuries, along with at least 5 missing.

1976 Big Thompson Flood MemorialLvaughn7, CC BY-SA 4.0, Wikimedia Commons

Big Thompson River Flood

Heavy rainfall caused the Big Thompson River in Colorado to crest. The crest was caused by a stalled thunderstorm complex that produced rainfall totals of 12–14 inches in record time.

People were instantly swept away without warning.

Big Thompson River Canyon floodDenver Post, Getty Images

Big Thompson Canyon, Colorado

A total of 7.5 inches of rain fell in one hour, totaling over 14 inches in only a few hours. Property damages reached over $190 million.

Big Thompson River floodSteve Larson, Getty Images

Mississippi River, 1993

Date: May-October 1993
Cause: Extreme weather and hydrologic conditions

This flood is often known as The Great Flood of 1993, and is among the costliest and devastating to ever occur in the U.S., with over 50 fatalities.

Great Flood of 1993Unknown Author., Wikimedia Commons

Mississippi River Flood

The waters stayed at flood stage for 81 consecutive days. Property damages reached over $30 billion.

Great Flood of 1993Markkaempfer, CC BY-SA 3.0 , Wikimedia Commons

Tropical Storm Allison, 2001

Date: June 5-20, 2001
Cause: Tropical Storm

A massive flood that inundated Texas was the result of Tropical Storm Allison, which lasted unusually long for a June storm—totaling 16 consecutive days—dumping torrential rain continuously.

Tropical Storm AllisonButch DuCote, Wikimedia Commons

Tropical Storm Allison

About 55 fatalities occurred, with 23 of them being in Texas alone. Property damage was estimated at over $15 billion.

flooding from Tropical Storm AllisonGalveston National Weather Service, Wikimedia Commons

Hurricane Katrina, 2005

Date: August-September 2005
Cause: Hurricane & Engineering flaws in the flood protection system

This flood is the costliest natural disaster in U.S. history, with over 1,800 fatalities and millions of people left homeless.

Hurricane Katrina of 2005The U.S. National Archives, Picryl

Hurricane Katrina

Engineering flaws in the flood protection system, particularly the levee around the city of New Orleans, is the cause of the massive flooding that ensued. Eventually, 80% of the city was completely flooded.

Property damages were over $200 billion.

Hurricane Katrina of 2005 floodJocelyn Augustino, Wikimedia Commons

Ka Loko Reservoir Flood, 2006

Date: March 14, 2016
Cause: Inadequate dam maintenance & heavy rainfall

The Ka Loko reservoir dam had not been adequately maintained prior to a heavy rainfall that caused the dam to burst, sending a 70-foot wall of water surging downhill to the town of Kilauea, Hawaii.

Kaloko BreachPolihale, CC BY-SA 3.0 , Wikimedia Commons

Ka Loko Reservoir Flood

The flood took the lives of seven people—including children and a pregnant woman. The owner of the damn was charged for the fatalities and reckless endangerment.

Kaloko DamageUnknown Author, CC-BY-SA-3.0, Wikimedia Commons

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