At least 20 girls are missing from an all-girls Christian summer camp in South Texas after catastrophic floods struck the area in the wake of severe overnight storms.

A major search and rescue operation is continuing through the night in Texas after flash floods killed at least 24 people and left many girls missing from a Christian summer camp.

Texas Lieutenant Governor Dan Patrick said authorities were searching for 23 girls listed as unaccounted for among more than 700 children who were at a summer camp when it was swept by floodwaters.