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.

With hundreds confirmed dead or still missing, questions remain about the local response to flood warnings. Meanwhile, lawmakers will weigh measures to mitigate future disasters.

In what experts call "Flash Flood Alley," the terrain reacts quickly to rainfall steep slopes, rocky ground, and narrow riverbeds leave little time for warning.

The deadly Texas floods have brought the state's approach to land approvals, especially in flood-prone areas, under more scrutiny.

Kerr County failed to secure a warning system, even as local officials remained aware of the risks and as billions of dollars were available for similar projects.