The risk of the catastrophic flooding that struck Texas Hill Country as people slept on July 4 and left at least 120 dead was potentially underestimated by federal authorities, according to an ABC News analysis of Federal Emergency Management Agency data,

At least 27 campers and counselors at Camp Mystic perished in Friday's floods, with the total death toll in the floods now surpassing 100.

The data also highlights critical risks in other areas along the Guadalupe River in Kerr County, revealing more than twice as many Americans live in flood prone areas than FEMA's maps show.

Many camps in the Guadalupe river region are adjacent or are partially inside high-risk flood zones, according to maps from the Federal Emergency Management Agency.

Kerr County had discussed buying such things as water gauges and sirens after previous flood disasters. But as with many rural Texas counties, cost was an issue.

Records released Tuesday show Camp Mystic met state regulations for disaster procedures, but details of the plan remain unclear.

Catastrophic flooding struck central Texas on Friday as the Guadalupe River surged by more than 20 to 26 feet within 90 minutes, causing widespread devastation and forcing mass evacuations in Texas Hill Country. At least 80 people have been killed in the floods while others remain missing or displaced and more than 850 people required rescuing.

Experts suggested that more data and education are needed as Texas and the rest of the country build in known flood plains.