Days of torrential rain in Washington state has caused historic floods, stranding families on rooftops and washing over bridges.

Experts warn that more flooding expected Friday could be catastrophic. Washington is under a state of emergency, with evacuation orders for tens of thousands.

Video from the U.S. Coast Guard shows a helicopter crew from Coast Guard Air Station Port Angeles rescue at least four people from flood-surrounded homes in Sumas, Washington.

The U.S. Coast Guard said a rescue swimmer who was lowered down remained at the home during the initial hoists and was later recovered by another Coast Guard crew.