America's 30 Most Catastrophic Floods Throughout History

Deadly waters

Home to vast plains and some of the mightiest rivers in the world, America has always been susceptible to flooding. Some parts of the country are more prone to flash flooding than others – but climate change has brought more extreme weather to all corners of the USA, and often to communities who are not properly prepared.

Click or scroll through as we take a closer look at some of the most deadly, dramatic and destructive floods in US history.

1889: Johnstown Flood, Pennsylvania

When the South Fork Dam in Pennsylvania collapsed on 31 May 1889, the Red Cross had only been formed for eight years. The Johnstown Flood was its first major peacetime disaster relief effort and volunteers were shocked by the sheer scale of the devastation. In total 2,209 people were killed, 1,600 homes flattened and the busy transport hub of Johnstown completely destroyed. The raging waters had tossed heavy locomotives like they were toys and bodies were found as far away as Cincinnati. The Great Flood, as it became known, remains one of the worst natural disasters in US history to this day.

1900: Galveston hurricane, Texas

On 8 September 1900, a deadly Category 4 hurricane, with winds estimated to be up to 145 miles per hour (233km/h), tore through Galveston in southeastern Texas. The hurricane triggered severe flooding, with angry waves pounding the little island city and leaving great swathes of it underwater. It is still regarded as one of the worst natural disasters in US history, with an estimated 6,000-12,000 lives lost. This is made all the more poignant as many of those lives could have been saved if meteorologists had taken warnings about the size and direction of the storm from their counterparts in Cuba more seriously.

1903: Heppner Flood, Oregon

Around 250 people are said to have died in the Oregon town of Heppner when heavy rain in the Blue Mountains triggered a flash flood that saw a 40-foot (12m) wall of water rush along Willow Creek. The flood waters wiped out much of the town and it remains the deadliest natural disaster in Oregon history. The death toll could have been much higher but for a steam laundry building on the southern edge of Heppner acting as a dam before being washed away. The several minutes it held back the waters gave many in the town a chance to reach higher ground.

1907: Pittsburgh Flood, Pennsylvania

When torrential rain and meltwater caused the three rivers of Pittsburgh to burst their banks on 16 March 1907, it was the city’s livelihood that took the biggest blow. Homes were lost and between six and 12 people lost their lives, while the economic impact of the flood was felt for decades. The destruction of local mills and industrial plants saw many businesses close and thousands of people lose their jobs. Economists at the University of Pittsburgh estimate that the city suffered damages amounting to a staggering $5 million.

1911: Austin Dam Failure, Pennsylvania

Built in 1909, the Bayless Paper Mill was meant to be the savior of the tiny Pennsylvanian town of Austin, creating jobs and bringing money to the area. But that relationship turned deadly on 30 September 1911 when the concrete gravity dam built to serve the mill collapsed, releasing floodwater that killed 78 people and caused $10 million in property damage. Parts of the dam still stand today and the victims are remembered and honored in the Austin Dam Memorial Park.

1913: The Great Flood, Ohio

In March 1913 so much rain fell that rivers across Ohio burst their banks. Considered the state’s greatest ever weather disaster, the state-wide flood was brought on by storms over three consecutive days, causing homes, bridges and railways to wash away. The town of Dayton was particularly hard hit when the equivalent of the month flow from Niagara Falls flowed down the Great Miami River, bursting the levees and flooding the town with 20 feet (6m) of muddy water. It’s thought that around 65,000 people across the state were left homeless, while more than 400 lost their lives.

1913: Brazos River Flood, Texas

Most of the time the cotton farmers in Freeport, Texas, were thankful for the periodic flooding of the Brazos River. Like the Nile in Egypt, the floodwaters brought nutrients to the vast agricultural plains and increased crop yields. But on 5 December 1913, heavy rain saw the swollen river burst its banks, destroying crops and much of East Waco. The result was 177 deaths, damages of $8.5 million and the building of a series of dams to temper the river’s destructive force.

1921: San Antonio Floods, Texas

Locals have long called the San Antonio River Basin ‘Flash Flood Alley’, a nickname well and truly earned on 9 September 1921, when the remnants of a Category 1 hurricane dumped 21 inches (53cms) of rain on the region. Damages totaled $56 million at today’s rates and at least 51 people perished, mostly along the San Pedro and Alazan creeks.

1927: Great Mississippi Flood, Arkansas, Mississippi and Louisiana

One of the most devastating river floods in US history took place in April 1927, after months of extreme rainfall swelled the Mississippi Delta and collapsed the entire levee system along the river. The flooding inundated nearly 23,000 square miles (59,570sq km) of land in 170 counties, across seven states. The catastrophe, which hit Arkansas, Mississippi and Louisiana the worst, drove around 930,000 people from their homes and it is thought that around 250 people died. More than 200,000 African Americans lost their homes, contributing to the Great Migration, an event which saw six million African Americans leave the rural south for the more urban north.

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1928: St. Francis Dam Collapse, California

The St. Francis dam was a storage reservoir in the San Francisquito Canyon that was part of a complex aqueduct system that served Los Angeles 40 miles to the south. It was built by William Mulholland, a self-taught engineer, who signed it off as safe on 12 March 1928, the very day it collapsed. 12.4 billion gallons of water barreled down the canyon towards the Pacific Ocean, killing around 450 people and wiping out the communities of modern-day Valencia and Newhall, as well as Castaic Junction, Fillmore, Santa Paula and Bardsdale. Ruins of the dam can still be seen today, known locally as ‘Tombstone.’

1936: Pittsburgh Flood, Pennsylvania

Residents of Pittsburgh in Pennsylvania are no strangers to flooding but on 17 and 18 March, they suffered the worst in their history. Torrential rain saw flood levels peak at a staggering 46 feet (14m), destroying more than 100,000 buildings and causing damages of about $300 million. Known as the Great St. Patrick’s Day flood, it took around 100 lives. But it also led to the construction of a dam to prevent future floods of the same magnitude.

1937: Ohio River Flood

After the Great Depression and the Dust Bowl the residents along the Ohio River were already down for the count. But heavy rains in January 1937 delivered the knockout blow, causing the entire Ohio River to flood, from Point Pleasant in West Virginia down to its confluence with the Mississippi at Cairo, Illinois. The flooding left an estimated 350 people dead and another million homeless. Businesses were devastated too. The industrial section of Cincinnati (pictured) sat underwater for months. The cost of damage along the whole river totaled $500 million.

1938: Los Angeles Flood, California

Between February and March of 1938, two Pacific storms swept across the Los Angeles basin, generating a year’s worth of rainfall in just three days. Multiple rivers burst their banks and flooded the coastal plain and valleys as well as the metro area. The flood turned Greater Los Angeles into an island, reachable only by radio. Actor Robert Taylor had to saddle up his horse and ride two miles (3.2km) to get out of his flooded ranch near Chatsworth while actress Lucille Ball had to rescue her terrier, found swimming in four feet (1.2m) of water in her basement.

1938: Great New England Hurricane, New York and Connecticut

A hurricane that hit Long Island on 21 September 1938 provoked a devastating storm surge. Pushed by winds which reached up to 186 miles per hour (299km/h), the surge swept entire coastal communities in central and eastern Long Island and southeastern Connecticut into the sea, taking the lives of around 600 souls and destroying entire towns. Actress Katharine Hepburn lost her Connecticut beach house but considered herself lucky to be alive.

1955: Connecticut Floods

On 19 August 1955, back-to-back hurricanes saturated the land and river valleys of Connecticut causing the Shepaug River, Mad River, Still River, Farmington River, Quinebaug River and Naugatuck River to burst their banks and flooding the towns of Farmington, Putnam, Naugatuck, Waterbury and Winsted. Ninety people lost their lives and property damage was estimated at more than $1.9 billion in today’s money. After the floods subsided a campaign of community tree spraying (pictured) using an insecticide mixture containing 5% DDT was conducted to control flies.

1972: Black Hills Flood, South Dakota

On the evening of 9 June 1972 heavy thunderstorms dumped 15 inches (38cm) of rain on the eastern foothills of the Black Hills of South Dakota. Debris began to clog the spillway of the Canyon Lake Dam and at approximately 10:45pm the dam failed, sending 50,000 cubic feet per second (1,416 cubic meters per second) racing through Rapid City as many of the residents slept. In total 238 people died, 3,057 were injured and 1,335 homes were destroyed. There was over $160 million in damages including 5,000 destroyed automobiles, mostly in the dealership along East Boulevard (pictured).

1972: Buffalo Creek Flood, West Virginia

Tragedy struck the small mountain communities of Buffalo Creek in West Virginia on 26 February 1972, when three coal slurry dams failed and sent a torrent of 130 million gallons of silt, water and coal waste roaring through the narrow valley. Hundreds of homes and vehicles were destroyed, thousands were left homeless and 125 lost their lives. “It looked like a battlefield,” said reporter Mannix Porterfield. “As if some foreign enemy had flown in and nuked the place.”

1972: Hurricane Agnes, Eastern States

When President Nixon (pictured) came to view the damage caused by Hurricane Agnes, the scale of its impact became immediately apparent. Although the city of Apalachicola bore the brunt when Agnes landed on 19 June 1972, the hurricane went on to flood eight states across the eastern part of the country and kill 122 people. New Jersey, Pennsylvania and Maryland were hardest hit, with experts estimating the cost in damage to property and industry at a staggering $18 billion in today's currency, making Agnes the costliest ever hurricane in 1972. 

1976: Big Thompson Canyon Flood, Colorado

The Big Thompson Canyon Flood in Colorado on 31 July 1976 remains the state’s deadliest natural disaster. In just over an hour, a storm dumped a year's worth of rain in many areas. Such was the rapid intensity of the flood that many residents had little to no warning that a 20-foot (6m) “wall” of water was sweeping down the canyon towards them. One hundred and forty-four people lost their lives that day, five of whom have never been found.

1977: Johnstown Flood, Pennsylvania

Johnstown in Pennsylvania had already experienced one of the deadliest floods in US history in 1889 when 2,209 people lost their lives. When history repeated itself on 19 July 1977 they were better prepared. A series of severe thunderstorms saw local rivers swell and break their banks, but despite the severity of the flooding, improved control infrastructure meant that the loss of life remained tragic but relatively limited at 84. Having said that, the disaster prompted the city to enhance early warning systems and educate residents on flood safety and preparedness.

1978: Northeastern Blizzard, New England, New York and New Jersey

The Northeastern Blizzard of 1978 will be remembered mainly for the blinding snowstorms and frigid temperatures it brought to New England, New Jersey and New York City in early February. The hurricane-force winds, white outs and snow drifts trapped drivers on the road and families in their homes. But most of the damage was caused by the storm surge, combined with spring high tides, that caused severe flooding and destroyed many homes on Long Island Sound and Cape Cod Bay.

1993: Great Flood, Midwest

As river floods go, the Great Flood that washed over vast swathes of the Midwest in the summer of 1993 rates is considered one of the most devastating and expensive in modern US history. At least 50 lives were lost, 50,000 homes destroyed and over 17 million acres of land left lying under water for more than three months. When the land finally dried out, it remained unusable for years, costing an estimated $15 billion in lost earnings across Illinois, Wisconsin, Missouri, Iowa, Minnesota, Kansas, Nebraska, South Dakota and North Dakota – the nine states affected.

1996: Northwest Floods, Oregon and Washington

In February 1996 unseasonably warm weather, record-breaking rain and melting snow caused widespread flooding across Oregon and Washington in the Pacific Northwest. The flooding in Willamette Valley in Oregon was particularly bad, spreading west to the Oregon coast and east to the Cascade Mountains. The floods were directly responsible for around eight deaths and famously swamped the Chehalis-Centralia airport in Washington.

1998: South Central Texas Floods

On the weekend of 17 to 18 October 1998 a ‘once-in-500-year’ flood hit San Antonio and South Central Texas, killing 25 people and causing more than $500 million in damages. The torrential rainfall had caught meteorologists by surprise when a pair of hurricanes over the Eastern Pacific unexpectedly came up against a stationary cold front. The resulting flash flood washed out many bridges and roads, with many of the lives lost from motorists driving through low water crossings.

2005: Hurricane Katrina, Louisiana

It’s hard to believe now, but as the vicious winds of Hurricane Katrina lashed the southwest of the US on 29 August 2005, authorities thought New Orleans had "dodged a bullet". The city was never directly struck by Katrina, but the violent storm surge that followed meant that their optimism was misplaced. The city’s neglected levee system breached, causing catastrophic flooding, with many people taking to their rooftops to await rescue. The storm took more than 1,800 lives and left millions homeless. It remains the costliest natural disaster in US history.

2012: Hurricane Sandy, New York and New Jersey

Hurricane Sandy slammed into New York and New Jersey on 22 October 2012 and is considered to be one of the most damaging storms ever to make landfall in the US. Much of New York City was flooded, including lower Manhattan, Brooklyn and Staten Island. Thousands of homes were destroyed and there were major power outages all along the East Coast. At its height, Sandy’s tropical-storm-force winds were around 800 miles (1,400km) across – roughly the distance between New York City and St Louis – and in all 233 people lost their lives.

2017: Hurricane Harvey, Texas

Hurricane Harvey hit Texas with 27 trillion gallons of rain, making it the wettest hurricane to hit the US. The resulting floods inundated hundreds of thousands of homes, displaced more than 30,000 people and led to more than 10,000 rescues. There were 68 fatalities and the state was left with a damage bill of $125 billion.

2022: Yellowstone River flooding, Montana, Wyoming and Idaho

Over 10,000 visitors were evacuated from Yellowstone National Park on 13 June 2022 when unprecedented rainfall and snowmelt burst the banks of Yellowstone River. Floodwaters quickly swallowed sections of bridges and roadway, trapping tourists and hampering rescue efforts. The US Geological Survey (USGS) announced that the devastating flood was a one in 500-year event and the park was not reopened until over a week later.

2022: Kentucky Floods

Devastating floods swept across Kentucky in late July, killing at least 39 people and causing catastrophic damage. The Appalachian region of eastern Kentucky was the worst hit, with President Joe Biden declaring it a "major disaster". The state saw eight to 10 inches of rainfall in a 24-hour period, with experts calling it a one in 1,000-year rain event. Thousands of residents were displaced as houses were washed away and as many as 50 bridges destroyed.

2023: California Floods

In January 2023, a series of storms lined up over the Pacific and took turns battering California with high winds and heavy rain. Meteorologists dubbed the prolonged bout of precipitation an ‘atmospheric river’ and by 11 January placed 90% of the state under flood watch. By the end of the month, California had endured record rainfall, catastrophic damage to property and 22 fatalities. Risk analysts Moody's estimated the cost of the damage to the state to be between $5-$7 billion.

Read on to learn about America's most violent storms

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