Graphics: Where the Texas floods happened and how high the waters rose

Most of the reported deaths in the July 4 floods occurred in Kerr County, Texas, along the Guadalupe River. Provisional river gauge data from the U.S. Geological Survey, recorded at various points along the river, showed water levels spiking to record levels over the course of a few hours.

The river gauge closest to Camp Mystic is about five miles downstream of the camp, where the south and north forks of the Guadalupe River merge. It recorded a rise of more than 25 feet in two hours, before going silent for the rest of the day.

The website for the National Water Prediction Service lists what might happen if a river gauge hits certain levels. For the Guadalupe River at Hunt river gauge — the one downstream from Camp Mystic in the chart above — one might expect to see:

• “Major flooding” at camps along the south fork of the river (an area that includes Camp Mystic) at 25 feet
• “Disastrous life-threatening flooding” at 32 feet

The area is known for being susceptible to flash flooding. Ana Campbell of Texas Public Radio reported:

As any Texan knows, the weather here is unpredictable. That’s because of the state’s unique position between cold, dry air from the north and moist, warm air from the Gulf of Mexico. Central Texas in particular is prone to intense rainstorms. Water fills the Colorado and Guadalupe rivers and their tributaries, making the area a popular destination for boaters and swimmers.

But when certain weather patterns collide like they did on Friday, the area is inundated with water that rushes through the hills and canyons. The abundant limestone keeps the water from soaking into the ground, so it rushes into the valleys, Sarah Spivey, a meteorologist with KSAT, told NPR.