The official tally of storm-related deaths across Texas rose to 131 on Monday as authorities warned of yet another round of heavy rains 10 days after a Hill Country flash flood that transformed the Guadalupe River into a killer torrent.

Rainfall amounts of 1 to 2 inches with isolated amounts of 3 to 5 inches are possible, the National Weather Service said.

At least a further 166 remain missing, with officials fearing the death toll could soar. Twenty-seven young girls and staff members were killed at Camp Mystic, an all-girls Christian summer camp situated on the bank of the Guadalupe River.