Law enforcement and rescue personnel are steaming over the latest Internet daredevil stunt, which marries two of Minnesota's proudest pastimes — defying the cold and plunging into open water.

On Wednesday night, a jumper's embrace of the fad — informally called the cold-water challenge — resulted in a lot of wasted time, perilous duty and precious resources for rescuers, the Hennepin County Sheriff's Office said Thursday.

The man jumped off the Hwy. 610 bridge over the Mississippi River just south of the Coon Rapids Dam. Law officers didn't know he was wearing a life jacket and easily made it to shore.

As he was drying off and warming up somewhere, first responders were feverishly hunting for him in the dark water. The long list of agencies involved included Brooklyn Park police and fire, Fridley fire, Coon Rapids Fire, the Department of Natural Resources, a State Patrol helicopter and county water patrol boats.

Hours after it began, the search was called off when authorities found the man's plunge video on YouTube. He and his videographer could face charges.

"In this particular case, the river was flowing fast, it's night, there was a strong current and obstacles in the river that can be dangerous," said Brooklyn Park Police inspector Mark Bruley, who was unaware of the fad before Wednesday. "As first responders, we know we are going to put ourselves as risk … but I don't unnecessarily want to put our staff in these situations."

In the basic cold-water scenario, the challenge is made when one person — usually a college or high school student — uses social media to "nominate" another to choose between a cancer donation and a jump into a cold lake or river. Lately, the dares have moved in less charitable directions. For example, students might nominate a friend and provide the option of delivering a case of beer or taking a plunge.

A 24- or 48-hour "deadline" is provided. Video proof of the dive must be posted online.

It's all meant in fun, but with Minnesota's lakes still icy-cold and rivers running high, fast and murky, the stunts could easily be deadly. In no-nonsense terms, law enforcers have been warning jumpers of the risks both to themselves and would-be rescuers.

Not to mention, they add, it's illegal to jump from some piers or to swim in navigation channels.

Last week, a U.S. Army Corps of Engineers employee in Duluth stopped a young adult from jumping off a Duluth pier into the churning shipping canal, warning of the cold-water "gasp reflex" that can cause a swimmer to drown quickly.

In Michigan a man reportedly fractured his neck and is paralyzed after a jump.

A stunt, not a sport

Minnesotans may feel a special affinity for the "in your face, Mother Nature" flavor of the stunt. Even hometown music hero Prince featured a racy variation on the stunt two decades ago in the movie "Purple Rain" when he tricked a paramour into wading half-naked into icy waters, then smirked, "That ain't Lake Minnetonka."

For many young people, the amphibious activity has joined cinnamon snorting in the annals of stupid, attention-seeking stunts.

Unlike sanctioned open-water swims and dives that are carried out legally and with safeguards, the Internet challenges aren't supervised.

Experienced open-water swimmers, especially those who go into frigid bodies of waters like Lake Superior, know to take precautions, often wearing insulated wet suits.

Even in the summer months, sanctioned lake-swim contests are closely supervised.

'Go where you know'

Logan Boese, a sophomore at Gustavus Adolphus College in St. Peter, said he noticed the popularity of plunge videos among college friends about a month ago. Now, he said, the activity has spread to high school students in his hometown of Slayton, Minn.

When Boese's fraternity was "nominated" to jump into the Minnesota River, he declined. He didn't like the message or the method. "Individuals are saying that they would rather jump in a very cold body of water instead of giving money to charity," he said.

As a summer camp lifeguard, Boese is aware of the risks of jumping into unfamiliar waters, and also knows there is not safety in numbers. "When you have big groups of people, it's much easier to lose people and you can't see them under water," he said.

Master Chief Petty Officer Robert Pump, who is in charge of the Coast Guard in Duluth, knows that some young people simply won't heed warnings. Nonetheless, he issued one.

"I encourage you to go slow, go with friends, and go where you know," he said.