(CNN) -- Volunteers are taking to the streets of Miami, Florida, this Super Bowl weekend to inform teenage girls of alternatives to working as prostitutes.

Just as Miami's hotels, restaurants and retail stores are seeing a bump in business for one of the biggest sporting events of the year, law enforcement and social service agencies say they are also witnessing a spike in trafficking of underage sex workers.

"Many social service agencies and law enforcement agencies recognize that there was an increase of victims of trafficking during last year's Super Bowl," said Regina Bernadin, Statewide Human Trafficking Coordinator for the Florida Department of Children and Families.

"That correlates with research that whenever there's a convention, a concert or a large event, traffickers will bring girls to the area to serve the influx of visitors," she added.

Girls and young women, as well as their pimps, come from as far as New York and Texas to meet the increased demand, says Brad Dennis, director of search operations for KlaasKIDS Foundation, which is spearheading the outreach effort.

"It's just that party culture," Dennis said. "Super Bowl is an entertainment event and everyone wants to come down and party and when you throw that mix into an area with lots money to spend, it's a traffickers' playground."

Due to the clandestine nature of underage sex trafficking, it's hard to track the exact number of girls who are brought in for the Super Bowl and other big events. But a look at online escort listings gives some clues, Dennis said.

One free online site offered 38 ads for Miami on January 16, but more than 200 on Saturday night, he said. It was impossible to tell how many of the advertised escorts might be underage.

On less high-profile weekends in Miami, Trudy Novicki, Executive Director of Kristi House, said her organization looks at the number of reported runaways as an indicator of how many girls could be working in the sex trade.

"We know that a very high percentage of runaways will end up being approached by a pimp within 72 hours of hitting the streets and they will be prostituted in order to survive on the streets," Novicki said. "So we know there is an extremely high correlation between runaway juveniles and underage prostitution.

Kristi House is also helping to coordinate the Super Bowl weekend outreach, Novicki said.

The profile of a typical runaway cuts across socio-economic lines, Novicki said, but many of them leave home to escape some form of abuse.

In an effort to reach those girls, state and local law enforcement agencies are teaming up with social service agencies to coordinate nighttime outreaches to girls on the streets.

Starting Wednesday, small teams of three or four volunteers have set out each night scoping the streets for potential trafficking victims, covering ground from Fort Lauderdale to South Beach to Hialeah. The hard part isn't locating the girls but finding an opportunity to approach them without drawing the attention of their pimps, said volunteer Eddy Ameen.

"Safety's always an issue because we know the girls aren't alone. We have to make sure we're not presenting potential harm to them," said Ameen, executive director of StandUp For Kids Miami.

If they get a girl's attention, they hand her a card with a hot line number for resources on how to get out of "the life," Ameen said.

"It's usually a very brief encounter -- just a few minutes, if that. Some may not call the next day or the day after or ever. We can give out card 100 times and maybe five will call. But if they do, we've made a difference," he added.

Another component of the operation aims to educate hotels and the hospitality industry on how to spot sex-trafficking operations on their premises and report it -- an approach that yielded the majority of leads at last year's Super Bowl in Tampa, Florida, according to Dennis.

"Last year we put together 21 leads that we gave to law enforcement, most of them from business owners or hotel owners basically stating I believe I have a trafficker and his girls stay at my hotel," he said.

"They'd see a lot of traffic coming and going, or girls standing out on corners.," Dennis added. "Those are all obvious signs, but good on them for actually reporting it."

The epidemic of underage sex trafficking isn't contained to Super Bowl weekend. An estimated 100,000 girls in the United States are under the control of a pimp or trafficker, according to Shared Hope Intermational, a nonprofit that works to combat worldwide sex trafficking.

It's a reality that groups like KlaasKIDS, StandUp For Kids and Kristi House encounter daily, Ameen said.

"The common perception is that the girls enjoy it, they make money, they're independent or they do it by choice. But when you work with young people selling their bodies, it's not a choice. It's a way to survive," he said.

"I don't want the idea to go away when Super Bowl ends. The reality is that it's more concentrated on Super Bowl weekend, but they're still out there come Monday morning."