Maps show how heavy rainfall and rocky terrain helped create the devastating Texas floods that have killed more than 120 people.

The July 4 Texas Hill Country flash flooding event is the latest to hit the region known as “Flash Flood Alley,” as Texas continues to lead the U.S. in flood-related deaths. The greatest number of flood deaths in the U.

Central Texas is infamous for its flash flooding and arid soil, hard-packed ground into which water does not easily infiltrate. So when rain hits the ground, it runs off the region's hilly terrain and canyons and accumulates into creeks and rivers rapidly, overwhelming them, causing them to rise quickly.

The first weather emergency alert sent by the National Weather Service with urgent language instructing people to "seek higher ground now" was sent at 4:03 a.m. local time.

Weather model data shows the National Weather Service had reason to warn of higher flood risks. Still, meteorologists say the agency made reasonable predictions.

There are two types of natural disasters in this country. Sometimes, it’s the weather that’s getting worse, as climate change leaves Americans exposed to new risks in places they thought were safe. Sometimes, it’s the land use that’s getting worse, as high costs and lack of regulation push people into locations with long-standing known dangers.

Kerr County failed to secure a warning system, even as local officials remained aware of the risks and as billions of dollars were available for similar projects.

Weather models that meteorologists use to predict thunderstorm activity and heavy precipitation suggested on Thursday the possibility of 10 inches of rain — and even as much as 20 inches — across

Over the last decade, an array of local and state agencies have missed opportunities to fund a flood warning system intended to avert the type of disaster that swept away dozens of youth campers and others in Kerr County,