North Texas is known for a wide variety of weather including what some may consider a subtle threat…flooding.
DALLAS — Texas is well known for its weather extremes, from tornadoes to hailstorms and even occasional snowstorms. Between those, there is an even bigger threat that statistically is more deadly: flash flooding. Stretching from North Texas down to San Antonio along the I-35 corridor is the region referred to as “Flash Flood Alley.” This is one of the most flash-flood-prone areas in North America.
But what makes this stretch of Texas so uniquely dangerous when it comes to flooding?
Let me explain.
What Is Flash Flood Alley?
“Flash Flood Alley” is an informal term used to describe the area along Interstate 35, particularly between Dallas–Fort Worth, Austin and San Antonio. This corridor consistently experiences frequent, intense and fast-developing flooding events.
While not an officially designated region, Flash Flood Alley is recognized by forecasters and city planners due to its history of recurring floods.
Why North Texas Is Especially Vulnerable
North Texas sits at the northern edge of Flash Flood Alley and shares many of the same risk factors. The explanation is a bit complex, so let’s break it down.
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The region contains shallow soils, rocky terrain and thin vegetation cover. These features drastically reduce the land’s ability to absorb water. That is why rainwater runs off quickly, funneling into creeks, rivers and low-lying areas.
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Urbanization in DFW and surrounding areas adds impermeable surfaces (like roads and parking lots), increasing runoff and overwhelming storm drainage systems.
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North Texas sits where the collision of moisture-rich Gulf air collides with cooler, drier air masses from the north. This triggers powerful thunderstorms, especially in the spring and fall.
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North Texas is also positioned to receive moisture from the Pacific in addition to the Gulf.
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The high moisture environment can trigger heavy rainfall rates
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Storms often train over the same areas (i.e., multiple storms passing over the same region in a short period), dumping massive amounts of water in hours. Usually due to stalled fronts.
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North Texas averages several intense rain events per year
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The rivers and creeks in the region, like the Trinity River, often have steep gradients and narrow channels, which can rapidly swell.
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Urban creeks can rise several feet in minutes, often catching people unaware.
How to stay safe
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Turn Around, Don’t Drown: Never drive into flooded roads. Just 6 inches of moving water can knock you off your feet. One foot of water can carry away a small car.
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Stay Weather Aware: Download the WFAA app and know the latest by catching the forecast on WFAA+
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Know Your Area: If you live near a creek or in a low-lying area, pay close attention during heavy rain events. Have a plan in place.