Always known as the adventurous couple among their friends, Chris and Jessica Mullins experienced their first dip into the icy waters of the Tennessee River in 2009.

The Decatur residents have since joined more than 100 human polar bears who gather at Riverwalk Marina annually Jan. 1 to commence the new year with a shocking plunge feet-first into the river.

Jessica, who has sat out since her first plunge in 2009 but stood on the sidelines to watch her husband participate, plans to return to the frosty waters in 2013.

“I have made many plans and promises to myself for 2013,” she said. “The way I see it, so many seers and soothsayers said the world would end in 2012 — obviously, we are still here. 2013: the year they said would never come. Why not make it a year to remember?”

For polar bears who fear wintry temperatures, highs in the low 50s and mostly cloudy conditions with a chance of showers may make the New Year’s Day jump at noon a bit warmer and drying off a little tougher.

Decatur resident Alex White has watched his godfather Wayne Holliday, who is president of the local Polar Bear Club, submerge himself in the chilly waters of the Tennessee River since he was in elementary school.

Now a senior at Austin High School, White plans to trade his winter coat and gloves for swim trunks on New Year’s Day so he can follow in Holliday’s footsteps.

“It’s my senior year this year, so I thought, ‘Why not?’ ” he said. “I think I’m old enough now. I’ve been watching him do it for as long as I can remember every year.”

Since 1985, Holliday has jump-started each year with a plunge into the Tennessee River. For the first several years, Holliday said he could never convince anyone to join him for the jump on New Year’s Day.

“Nobody was foolish enough to go with me,” he said.

But the crowds soon began gathering, and gradually more than 100 residents across north Alabama began taking the plunge alongside Holliday each year.

“It’s shocking, but it’s always fun,” he said. “I always dread taking the plunge, but I always look forward to the event.”

Polar bear T-shirts will be available for sale at the event, and all proceeds will benefit Meals on Wheels. Sizes extra-large and smaller will cost $15, while sizes 2X and larger will be $17.

Last year, the Polar Bear Club raised more than $1,100 in T-shirt sales for the nonprofit organization.

Blaine Williams, a 10th-grader at Hartselle High School, plans to gather a group of friends to take the plunge for the first time on New Year’s Day.

“We just thought it would be something fun to do and a tradition to start with friends,” he said. “It’s going to be really cold, and that’s going to be kind of scary, but I think it’ll be fun.”