Floods are nothing new - communities across the country have faced them for centuries. But with today’s increasing flood risk, relying on the same approaches of the past is no longer enough. Modern technology now offers stronger, smarter, and more proactive flood-protection solutions than ever before.

Below, we explore the worst floods in US history, how they happened, and what modern homeowners and businesses can learn from them.

1. The Great Mississippi Flood of 1927

Often considered the benchmark for the worst floods in US history, the Great Mississippi Flood of 1927 remains one of the most destructive river floods ever recorded. Weeks of intense rainfall pushed the river past its limits, causing over 130 levee failures and inundating more than 27,000 square miles across several states.

2. The Johnstown Flood (1889)

The 1889 Johnstown Flood occurred when the poorly maintained South Fork Dam collapsed after days of heavy rain, sending a 40-foot wall of water rushing into the valley. Entire neighbourhoods were swept away within minutes, making it one of the deadliest dam-related disasters and among the worst floods in US history.

3. The Ohio River Flood of 1937

Unprecedented rainfall (more than 20 inches in some regions) caused the Ohio River to swell far beyond its banks. The flood lasted nearly a month, submerging downtown districts from Pittsburgh to Louisville and forcing almost one million people from their homes. Its widespread and prolonged impact makes it one of the worst floods in US history, and serves as a reminder that flooding isn’t always fast - a prolonged one brings far-reaching and devastating damage.

4. Hurricane Katrina (2005)

Hurricane Katrina stands near the top of any list of the worst floods in US history because of the catastrophic flooding in New Orleans after major levee failures. Over 80% of the city flooded, with water lingering for weeks. The event exposed the vulnerabilities of aging infrastructure and the overwhelming power of coastal surge.

5. The Great Molasses Flood (1919)

An unusual but historically significant event, the Great Molasses Flood occurred in Boston when a massive storage tank burst, sending a wave of molasses through the North End. The resulting 25-foot wave of molasses swept through streets at surprising speed, destroying buildings and claiming lives. Its scale and impact secure its place in discussions of the worst floods in US history, even though it wasn’t caused by weather.

6. The Red River Flood of 1997

A combination of rapid snowmelt, frozen ground, and heavy spring rain pushed the Red River to record-breaking levels. Grand Forks and East Grand Forks were hit hardest, with downtown areas engulfed and thousands of residents evacuated. The impact was far-reaching, as parts of Canada experienced flood damage. It remains one of the worst floods in US history for northern states.

Preparing for the Future by Learning From the Past

When examining the worst floods in US history, one theme stands out: no community is immune. Whether caused by storms, overflowing rivers, infrastructure failures, or industrial accidents, floods strike in ways that are often unpredictable.

While large-scale government infrastructure, like levees and drainage systems, plays an important role, it cannot guarantee complete protection. Property-level mitigation solutions, including custom flood panels and comprehensive preparedness plans, fill the gaps where public systems fall short.

For more information about our flood risk and how you can protect your property, contact us today to schedule a consultation.