What happened: State and local authorities said at least 81 people have died in flooding triggered by unrelenting rain Thursday night into Friday. What happened at Camp Mystic? Anguished parents await updates on the children still missing from a 99-year-old nondenominational Christian summer camp caught in the deluge.

Surviving campers sang hymns as they drove past the damage left by the floods. Days earlier, they were having fun and playing games at the all-girls’ Christian summer camp.

When too much rain falls for the ground to absorb, it runs downhill, pulled by gravity into streams, creeks and rivers.