Heavy rains fell quickly in the predawn hours of Friday in the Texas Hill Country, causing the Gaudalupe River to rise 26 feet in just 45 minutes.

Local officials warned the number of dead will likely rise and were due to give an update on Sunday morning, as search and rescue teams raced to find 27 girls missing from a camp near the Guadalupe River,

Rescuers searched for survivors at Camp Mystic on the bank of the Guadalupe River in Hunt, Texas, after deadly floods swept through the area on July 4.

Flash flood alley is a curved-shaped region about 300 miles long and 50 miles wide in central/south-central Texas, extending from north of Dallas to southwest of San Antonio. Its location, weather patterns, and geology often combine to create devastating floods.

A combination of steep terrain, shallow soil and a moisture-laden weather system that stalled over the Texas Hill Country caused the flash floods that killed at least 79 people Friday. The weather system that caused the flooding was fueled by moist air from the coastal plain that swept up the Hill Country’s steep cliffs,