Some camps in the region had to be evacuated, and local newspapers described how Camp Mystic was among those cut off from the outside world. According to a Kerr County history book, floodwaters at Camp Mystic almost reached the top of the dining hall’s stairs.

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

Radar data can estimate rainfall to a fairly accurate amount. The rain data in the case of the deadly tragedy that unfolded in the Texas Hill Country last weekend shows exactly why the area around Camp Mystic and the Guadalupe River, outside of San Antonio, had such a raging flash flood.