24 years since Tropical Storm Allison: The storm that changed everything

HOUSTON — On this day in 2001, Tropical Storm Allison made landfall near Freeport, Texas, becoming one of the most destructive tropical storms in U.S. history despite never reaching hurricane strength.

Allison formed quickly and hit the Texas coast on June 5, 2001, just nine hours after developing. But the real damage came in the days that followed. The storm stalled over southeast Texas from June 5 through June 8, unleashing catastrophic flooding across the Houston area and beyond.

Up to 40 inches of rain fell in northeast Harris County. Many areas saw more than 20 inches as the system lingered.

The floodwaters overwhelmed freeways, knocked out power to thousands, and even flooded hospitals in the Texas Medical Center.

In total, Allison caused over $9 billion in damage in Texas alone — a figure that grew even larger as the storm moved through other states.

In Texas, 23 lives were lost, most of them to flash flooding. Nationwide, Allison was ultimately responsible for 40 fatalities.

At the time, it became the costliest tropical storm on record and revealed critical weaknesses in Houston’s infrastructure.

Allison became a turning point in how cities prepare for extreme weather. In its aftermath:

• The Harris County Flood Control District launched major flood mitigation projects, including expanded bayou systems, new retention basins, and improved emergency communications.
• The storm forced a reevaluation of forecasting practices and public preparedness campaigns. Meteorologists point to Allison as proof that you don’t need a hurricane to see devastating impacts.

“This storm served as a wake-up call that even a weak tropical storm can have deadly and long-lasting impacts,” KHOU 11 Meteorologist Chita Craft said.

Now, 24 years later, the message remains clear: It only takes one storm.

With hurricane season underway, officials urge residents to stay ready. KHOU’s 2025 Hurricane Preparedness Guide is available for free to help families prepare for the unexpected. Download it now at KHOU.com.

• Landfall: June 5, 2001 (Freeport, Texas)
• Rainfall: Up to 40″ (NE Harris County)
• Fatalities: 23 in Texas, 40 total
• Damage: $9B in Texas alone
• Aftermath: Major investments in Houston flood control and forecasting

As we reflect on Tropical Storm Allison, remember: history doesn’t have to repeat itself — if we stay prepared.