The camp where 27 girls died successfully challenged initial risk designations by US regulators, according to reports.

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.

There are questions over why oversight was eased at Mystic Camp as it expanded in a hazardous floodplain, the AP reported.