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, satellite imagery and risk modeling.

At least 120 people have been found dead since heavy rainfall overwhelmed the river and flowed through homes and youth camps in the early morning hours of July 4. Ninety-six of those killed were in the hardest-hit county in central Texas, Kerr County, where the toll includes at least 36 children.