The mother and father of six children, mostly teenagers, killed Thursday after being dragged out to sea by powerful rip currents while on a family vacation in Florida.

The Pennsylvania family was enjoying the day at a  Hutchinson Island beach near Port St. Lucie Thursday afternoon when the 51-year-old father, 48-year-old mother, and two teen daughters were washed away by a rip current, according to the Martin County Sheriff’s Office.

The children were able to escape the current and attempt to aid their parents, but the conditions remained too dangerous, forcing them to swim to shore.

Ocean rescue teams spotted the unresponsive parents, hauled them to land, and performed CPR until medics arrived on the scene.

As the National Weather Service urgently advises, rip currents can be deceptively dangerous, draining swimmers’ energy without pulling them under. Calmness is key to survival.

“Trying to swim against a rip current will only use up your energy; energy you need to survive and escape the rip current. Do NOT try to swim directly into the shore. Swim along the shoreline until you escape the current’s pull. When free from the pull of the current, swim at an angle away from the current toward shore,” the website advises. The service also recommends never swimming alone and adhering to the motto, “If in doubt, don’t go out!”