Drone footage captured the group of great white sharks in Dana Point, California.
"You are paddle-boarding next to approximately 15 great white sharks," Deputy Brian Stockbridge announced via a loudspeaker.
Stockbridge was in a helicopter, flying off the coast of Dana Point in Orange County, Calif., at about 2 p.m. local time on Wednesday. And, indeed, swimming in the Pacific Ocean below and clearly visible from the air, were several great white sharks. Their fins rose menacingly from the water as they glided back and forth.
"They are advising you exit the water in a calm manner," Stockbridge added. "The sharks are as close as the surfline."
No one was hurt, and OC Lifeguards Chief Jason Young said the situation wasn't dire enough to call for an ocean closure, which only occurs when the sharks are more than 8-feet long and/or acting aggressive.
"We haven't had any reports of anyone being bumped or charged, just observations of them either swimming or breaching," he told the Ocean County Register.
But he added this isn't the first sign of great white sharks in the area lately.
"The report we got from the sheriff's was very similar to the reports we've had before with the juveniles in the area at Beach Road," he said. "We had dropped the advisory as of yesterday and put it back on today."
Authorities posted advisories up and down the beaches of Southern California following several shark sightings this week.
Last month, a woman was bitten by a shark while surfing at San Onofre State Beach and suffered severe injuries.
"It was definitely to the point, her hamstring was gone," Thomas Williams told the Ocean Country Register. "If she didn't receive immediate care, it was life-threatening."
"All of the back of her leg was kind of missing," Williams added.
While it's not uncommon to spot sharks along the Southern California coast, they seem to be appearing in greater numbers. This could be due to an increase in smartphones capturing video of the shark, but it also could be due to rising sea temperatures.
"El Nino conditions last year created warmer temperatures that enticed white sharks to linger along the Southern California shoreline into the winter and then return quickly again early this spring," Joshua Emerson Smith wrote in the San Diego Union Tribune.
Warmer waters bring out greater numbers of people, too, and they tend to go for longer swims, researchers say. With more humans and more sharks hanging out in the same place, shark attacks could climb.
Great whites can grow up to about 20 feet long and can weigh more than 4,000 pounds, although most adults measure between 11 and 16 feet, according to the Smithsonian.
Despite their predatory prowess and well-earned reputation as killing machines, great whites aren't actually all that dangerous to humans. Most people who get attacked by the legendarily terrifying fish survive, as nature writer Sy Montgomery told The Washington Post last year. Seals, it turns out, are their dish of choice.
"For a great white shark, a seal is a big juicy steak with a slice of chocolate cake," she said. "A person is an old piece of celery that's been sitting on the counter all day."
In the United States, the fatality rate for shark attacks was a mere 1.7 percent in 2014. Worldwide, the figure was nearly 13 percent, as the Atlanta Journal Constitution reported.
The best way to avoid an attack is to pay attention to lifeguards and steer clear of smaller fish, said Emerson, of the Union Tribune.
"If you find yourself surrounded by a massive school of bait fish," he said, "maybe it's time to paddle in or find a new surfing spot."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)