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.

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.

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.

Some regions in the mid-Atlantic are also facing risks of flooding. On Sunday, Tropical Storm Chantal flooded parts of North Carolina, where more than 10 inches of rain fell near the Chapel Hill area. The Haw River, near Bynum, North Carolina, crested to nearly 22 feet, the highest crest on record there, as a result of those heavy rains.

Days after flash floods killed over 100 people during the July Fourth weekend, search-and-rescue teams are using heavy equipment to untangle and peel away layers of trees, unearth large rocks in riverbanks and move massive piles of debris that stretch for miles in the search for the missing people.