Flash floods in Texas have killed nearly 90 people, many of them children. Heavy rains fell quickly in the predawn hours Friday in the Texas Hill Country, causing the Guadalupe River to rise 26 feet in just 45 minutes.

Crews picked through mountains of debris and waded into swollen rivers Monday in the search for victims of catastrophic flooding that killed nearly 90 people over the July Fourth weekend in Texas, including more than two dozen campers and counselors from an all-girls Christian camp.

( The Conversation) – Texas Hill Country is known for its landscapes, where shallow rivers wind among hills and through rugged valleys. That geography also makes it one of the deadliest places in the U.S. for flash flooding.