Atlantic City had its first fatalities on a guarded beach in at least three decades this weekend. This despite warning signs and extended lifeguard hours at one of the city's more popular - and dangerous - beaches.

"This was really an extraordinary event, and a tragic event at that," Beach Patrol Chief Rod Aluise said Monday, two days after a couple was pulled from the water near the jetty off Martin Luther King Jr. Boulevard.

Samuel Jackson and Thewinco Caesar were swimming with about three others before 7 p.m. Saturday when they went under the water and didn't resurface, Aluise said. They were pulled from the water and members of the the Beach Patrol worked to revive them, but the pair was later pronounced dead at AtlantiCare Regional Medical Center's City Campus.

There are signs at the beach entrances warning bathers to swim only while lifeguards are on duty, which is from 10 a.m. to 6 p.m. at most beaches. Hours have been extended at Martin Luther King and other areas that tend to see crowds and pose dangers.

Two red signs with white lettering near the site of Saturday's drownings warn: "Danger area, keep away."

But those signs aren't seen from every angle, said Kristin DeLuca, who was visiting the Atlantic City beach for the first time with her daughter Katie, 17. She searched the area Sunday night when she was trying to see what time the beach would open Monday. The only hours she said she could see were those on the lifeguard stands. From her spot on the beach Monday, the "danger" warnings were not visible.

"They need to have signs that say, 'Swim at your own risk,'" the Stroudsburg, Pa., woman said. "That definitely should be posted."

"They need to block off the beach there completely," Katie DeLuca said.

But her mother disagreed, saying she just thinks "they need better postings."

People's instincts would then be not to swim, the pair agreed.

But from his spot renting beach chairs, Peter Medina doesn't see people being deterred by either the signs or the guards. He has watched as lifeguards whistle people in at the end of the day, only to have them re-enter the water after the Beach Patrol is gone.

"They don't pay attention to the signs," said Medina, who lives in Miami but has summered here for six or seven years. "As soon as (the lifeguards) are gone, there are a bunch of people swimming."

That's what happened June 10, 2012, when a family went swimming at about 7 p.m., at the then-unguarded beach at King Boulevard.

Less than 10 minutes into their swim, the current pulled the group toward the jetty. Khitan Devine, 10, disappeared. His body washed up in Margate three days later. Since then, the hours at that beach and a few others have been extended to keep them guarded until 8 p.m.

But where the dangers are can change, Aluise said.

Piers, jetties and wooden groins can affect currents, explained Fire Chief Dennis Brooks, a former city lifeguard. Changing weather conditions and even sand shifts - especially the large ones seen from October's Hurricane Sandy - also can increase the dangers. In the area of Saturday's drownings, there is an outfall pipe, which Brooks said he believes Jackson became trapped under.

"The ocean is a dynamic force," Aluise said. "That area (at MLK) is not always as dangerous. Sometimes it's more dangerous than others."

That is why, he said, lifeguards keep an eye on the conditions and move people accordingly.

On Monday morning, lifeguard J.B. Magee was limiting bathers to waist-deep water around Mount Vernon Avenue. He blew his whistle while walking into the water toward a man who had ventured too far.

"That's one of the concerns you have as a lifeguard, keeping people out of danger," said city Public Safety Director Will Glass, who was a city lifeguard for 10 years. "Sometimes that's difficult. The current can grab somebody, a hole can form in the sand. These things happen in seconds.

City resident Michelle Johnson said she watched Saturday evening as lifeguards cautioned people away from the rocks. At one point, guards went out on two boats and a personal watercraft to move people away from the area where a lot of people were swimming, she said. About 15 to 20 minutes later, she heard them whistling warnings again.

Then, around 6:30 p.m., Johnson said lifeguards rushed back into the water, "headed into the same direction where they were telling people to move away from the rocks earlier," Johnson recalled. "I then saw a lifeguard from one of the boats dive into the water immediately and I remember thinking to myself, 'Someone went under.'"

Caesar, 22, of Darby, Pa., was found first, floating in the water. About 15 to 20 minutes later, witnesses said they saw a man run into the water after he spotted Jackson, 21, of Lowell, Mass.

"Being a nurse, I offered to help, but they had everything under control," Johnson said of the lifeguards. "I commend (them) for their hard work, professionalism and poise in such a tragic situation."

Lifeguards had made 47 rescues throughout the city that day, with 1,112 since Memorial Day, he said.

Both Aluise and Glass also commended the job the lifeguards did in trying to revive the pair.

"I want to emphasize how proud I am of the work they do day in and day out," Glass said.

Brooks said the Fire Department's Water Rescue Unit has been concentrating on more training, especially with the changing ocean conditions so far this season.

"Usually, it's more predictable," said Brooks, who had just finished a swim in the ocean Monday afternoon.

But always, people have to understand the water's power, say those who deal with it.

"When I was a lifeguard, I had someone ask me, 'Where's the deep end?'" Glass recalled. "Some folks are just unknowledgeable about the power of the ocean, the currents, the wave actions. They're used to swimming in swimming pools."

Contact Lynda Cohen:

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