Sunday, July 13, 2025

How Terrain in Texas Hills Turned Stalled Rainstorm Into Flood Disaster

Water cascaded down cliffs and swelled waterways when shallow soil failed to absorb the deluge

By Eric Niiler of The WSJ. Excerpts:

"A combination of steep terrain, shallow soil and a moisture-laden weather system that stalled over the Texas Hill Country caused the flash floods that killed at least 79 people Friday.

The weather system that caused the flooding was fueled by moist air from the coastal plain that swept up the Hill Country’s steep cliffs, condensed overhead, and for hours cascaded down those same cliffs. Narrow canyons then funneled the coursing water into creeks and rivers that rose and turned into deadly flash floods."

"Once a rainstorm develops, there is little place for the water to go. It’s a semiarid area covered by a shallow layer of soil over bedrock. The ground doesn’t absorb much rainfall, and runoff can cause shallow rivers and creeks to rise quickly, Sharif said."

"“We had a weak upper level disturbance from the west that helped destabilize the atmosphere and provide ascent of air in central and south central Texas,” Nielsen-Gammon said. “The last ingredient we had was a wind profile that allowed the storm to sit in place and redevelop over the same location for an hour or more.”

A separate low-pressure system fed the storm from the north."

"Up to 18 inches of drenching rain fell over a three-hour period early Friday in some locations."

All posts on this topic:

How Terrain in Texas Hills Turned Stalled Rainstorm Into Flood Disaster: Water cascaded down cliffs and swelled waterways when shallow soil failed to absorb the deluge 

The Texas Flood Green Herrings: Blame cruel nature, not DOGE, or weathermen, or climate change 

Why It’s So Hard to Link Extreme Weather Events to Climate Change: Attribution science examines how global warming fuels extreme weather, but making the connection is challenging 

The Texas Floods Were a Natural Disaster, Not a Policy Disaster: There's no evidence that cuts to the National Weather Service impacted the response to the weekend's tragic flash floods

 

 

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