Intense thunderstorms sweeping through the Rio Grande Valley are unleashing unleashed flash floods across multiple counties in Texas late Thursday into Friday, with authorities warning residents to avoid low-lying areas where water catchment and poor drainage are possible.

A flood emergency unfolded in South Texas after torrential rain submerged vehicles and killed at least three. In South Carolina, the Table Rock Complex Fire has expanded to nearly 17 square miles.

More than 20 inches of rain — about a half-year’s worth — fell in some areas near the border on Thursday and Friday.