TODAY | June 19, 2012
>>> back now at 7:43 with a warning about a danger at some of our nation's beaches. experts have issued an alert about powerful rip currents . nbc's kerry sanders with more on this story. kerry, good morning.
>> reporter: good morning, ann. again today the national weather service says there is a high probability for rip currents here in new smyrna beach, florida, also corpus christi , texas, and lake michigan . the problem is you can't see a rip current . often that silent threat can be deadly. along the atlantic coast more than just strong surf and invisible threat. on sunday lifeguards rescued dozens of swimmers from powerful rip currents in new smyrna beach. it was all too much for a 14-year-old boy trapped by a rip current . he drowned. nearby ormond beach same thing as a 66-year-old man drowned. rescuers couldn't get to him in time.
>> lifeguards pulled him to shore eventually. they did rescue efforts, cpr, and they were unable to bring him back.
>> reporter: more than 100 swimmers die every year from the current. this rescue caught on tape by the reality tv show , "ocean force." among the survivors now warning beachgoers of the hidden threat, 17-year-old erica hernandez. five years ago she was trapped in a rip off the east coast of florida.
>> i was going to die. i remember seeing this man say to me, i was on his shoulder and i was screaming, i'm going to die, i'm going to die. it was terrifying.
>> reporter: erica survived, but only because of the heroic efforts of a bystander, john carlos .
>> he's a hero, but he was a hero before that to me. he was my child.
>> reporter: his mother olga is torn by her only child's heroism that day, the 31-year-old everyone called j.c. saved erica . as he lifted her to safety and another bystander took her to shore, jl c. was pulled down by the same rip current .
>> when i see your son, i see a very strong man.
>> he's a good swimmer. yes, he was. very strong, very athletic, very fit.
>> reporter: strong, fit, but no match for mother nature . created by shifting sand , the powerful rip current pulls a swimmer directly away from shore. it's usually the exhaustion of trying to swim against that rip, combined with panic, that causes a swimmer to drown. the best advice if you're caught in a relationship, try to swim parallel to the beach. but experts say sometimes that's easier said than done. you during the last year, this lifeguard has rescued more than 100 swimmers.
>> when you rescue someone and revive them, what do they tell you.
>> they had no idea how strong it could come or there were currents that day. the most important thing i can tell everybody is just swim in front of a lifeguard tower. there's somebody there to help you.
>> reporter: that's a big problem. there are no lifeguards where people are swimming. i have biodegradable cookies to show where a rip current is. if you see green in the water, there's no rip current here because it it would be pulling straight out.
>> excellent information about how to protect from rip currents . thank you so much.