The History of Major US Floods: Lessons Learned

Floods That Changed Policy

The history of major floods in the United States is closely tied to the development of flood management policy. Each catastrophic event revealed gaps in preparation, response, and recovery that led to significant changes in how the nation approaches flood risk.

The Great Mississippi Flood of 1927 displaced over 600,000 people and led to the Flood Control Act of 1928, which gave the Army Corps of Engineers responsibility for flood control on the Mississippi River. The Johnstown Flood of 1889, which killed over 2,200 people, demonstrated the catastrophic potential of dam failures.

Modern Era Disasters

The Great Flood of 1993 on the Upper Mississippi and Missouri Rivers lasted for months, flooded 20 million acres, and caused $15 billion in damage. It demonstrated that levee systems can fail on a massive scale and led to increased buyouts of repeatedly flooded properties.

Hurricane Katrina (2005) killed over 1,800 people when levees protecting New Orleans failed. The disaster exposed fundamental flaws in the NFIP, federal emergency response, and the engineering of flood protection infrastructure. It led to a complete overhaul of New Orleans' levee system and significant reforms to FEMA.

Hurricane Harvey (2017) dropped unprecedented rainfall on Houston, flooding over 300,000 structures. It highlighted the consequences of building in floodplains and the inadequacy of existing stormwater infrastructure in rapidly developing areas.

Recurring Lessons

The same lessons emerge from every major flood: development in flood-prone areas increases losses, infrastructure designed for past conditions fails under changing conditions, flood insurance is consistently undervalued before disaster strikes, and recovery without insurance is devastating for families and communities.

Applying History to Your Decisions

Understanding flood history helps put current risk in perspective. Check the flood risk data for your area and consider that the worst flood in recorded history for your location may be surpassed in the future as conditions change.