It’s been a recipe for deadly waters on Northeast Florida beaches in recent weeks — warm temperatures drawing people to the shore to face an ocean churned up by nor’easters.

As high wind-driven waves pounded ashore, some raced back out with swimmers trapped in river-like runouts. These riptides caused three deaths since Thursday as well as dozens of rescues.

The latest victim was a 14-year-old boy caught in a rip current 15 to 20 yards from shore about 1:45 p.m. Sunday in Jacksonville Beach. Searchers could not find him, and his body turned up about 6:30 a.m. Monday in the surf near 17th Avenue North, according to Sgt. Thomas Crumley of Jacksonville Beach police. His name has not been released.

Riptides are powerful, channeled currents that flow away from shore and can tow a swimmer past the line of breaking waves, according to the National Weather Service.

Riptide conditions have been treacherous as beachfront red flags fly to warn beachgoers, said George Paugh, past captain of the American Red Cross Volunteer Life Saving Corps on Jacksonville’s beaches. Yet those coming to enjoy summer-like temperatures in recent weeks from elsewhere did not understand the danger, he said.

“We have had nor’easters with 30- to 40-mph winds for the past two weeks, and the volume of water is extensive and pushing more and more water on the beach. Then it gets trapped in the slews,” Paugh said. “The runouts we are having I have never seen before. There are waves on both sides and a river in the middle. They are rivers running out. They are very strong and people don’t understand it. … This is not a lake. It is very dangerous.”

Another change in the ocean bottom may be a reason for so many swimmers in distress, said First Coast News senior meteorologist Tim Deegan. Hurricane Matthew in 2016, then Irma in September, scoured out the sand in another direction, he said.

“I am talking about deep trenches going from south to north. When we get a hurricane, it scours out the sandbars offshore and makes for a sharp drop-off,” Deegan said. “I know personally there is a steeper drop-off, and I wouldn’t be surprised if it causes some people to startle or panic more than normal. … There were pretty strong waves. They were not particularly large, but they had a lot of power per foot.”

Read more on the Florida Times-Union.