🚨 What REALLY Causes Flash Floods?

A little water on the sidewalk seems harmless.

But when too much rain falls too fast — especially where it can’t soak into the ground — that gentle drizzle can become a powerful disaster.

🧠 What’s Going On?

Flash floods are exactly what they sound like — floods that happen in a flash.

They can begin in minutes or hours after heavy rainfall, especially in places with dry soil or hard pavement. Unlike slow-rising floods that build over days, flash floods crash through cities, neighborhoods, and roadways without much warning. And in the summer of 2025, that’s exactly what happened in Central Texas.

🚨 Texas Hill Country: A Real-Life Disaster

In early July, heavy storms hit Kerr County and the surrounding Hill Country region.

Over four months' worth of rain fell in just a few hours.The Guadalupe River surged more than 26 feet in under an hour.Entire roads were swept away. Homes and businesses flooded.And more than 100 lives were lost.

It became one of the deadliest inland flash floods in U.S. history — not because it was the biggest, but because it happened so fast.

🌧️ What Causes Flash Floods?

Flash floods can strike just about anywhere — but certain conditions make them more likely:

• Heavy rain in a short time

• Hard surfaces like roads and sidewalks that don’t absorb water

• Dry or already saturated soil that can’t take in more

• Hilly or mountainous terrain where water flows downhill fast

  Cities are especially vulnerable. All that concrete and pavement creates what experts call runoff — water that can’t soak in, so it races along the surface. And when that water builds up, it doesn’t ask for permission.

🔥 Why Are They Happening More Often?

Two big reasons:Climate change and urban growth.

Warmer air holds more moisture, which means more rain during storms. At the same time, growing cities replace forests and fields with parking lots and buildings. That combo creates the perfect recipe for sudden flooding — especially during intense weather events.

The Texas flood wasn’t just a fluke.It was a warning.

⚠️ Safety in a Flash

Flash floods are fast — and they can be deadly. Here’s what scientists, emergency crews, and our Curious Professors say you should know:

• Just 6 inches of moving water can knock a person down

• Just 12 inches can sweep a car away

• Floodwaters can hide sinkholes, sharp objects, or strong currents

• Always follow alerts — and if you see water across a road,<emphasis level="moderate">Turn around. Don’t drown.</emphasis>

  
  

🤔 Big Questions

Flash floods raise important questions for all of us:

• How should cities plan for sudden disasters?

• What can families do to prepare?

• Should we change the way we build roads, homes, or neighborhoods to handle more rain?

There’s no single answer — but understanding the risk is the first step toward staying safe.

🎧 Want More?

This blog post is based on our podcast episode:🎙 What REALLY Causes Flash Floods? Featuring Professor Punzworth, Professor Sagewell, Sunny Crisp, and Archivist Alex — together, they explore how flash floods form, why they’re increasing, and how the 2025 Texas disaster changed the way people think about water and weather.

🌊 Flash Flood Fast Facts

📈 Flash floods are the #1 cause of weather-related deaths in the U.S.

🚗 Just 12 inches of water can sweep away a car

🌍 Flash floods can happen anywhere — not just near rivers or coastlines

🔥 Climate change is increasing the risk of sudden, intense storms

💬 Discussion Question

If a flash flood happened in your area, would you and your family be prepared?What steps could you take today to stay safer tomorrow?