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,

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.

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.

At least 27 campers and counselors were killed at Camp Mystic during the devastating Texas floods. Some are still missing.

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

In some ways, out-of-towners were more vulnerable in the July 4 flood. At least 19 of the more than 100 people killed were from the Houston area.