The crowds at this year’s St. Paul Ice Fishing Show at RiverCentre is a reminder of the sport’s popularity as Minnesota waterways begin to freeze over.

“A lot of people love to get out ice fishing,” says Jason Mitchell, an exhibitor. “Don’t just assume if you see somebody that ice is good everywhere.”

Up to 25,000 people are expected to attend the event.

Amid the excitement of a new winter season, caution about thin ice is a watchword here.

“No fish is worth risking your life,” declares Vanessa Kaiser with the group Future Anglers of Minnesota.  

The Cambridge nonprofit teaches kids ice safety, encouraging youngsters to make sure they’re always accompanied by an adult and to learn proper safety techniques.    

“You’re always going to want to check the ice while you’re going out,” Kaiser explains. “So, drill holes as you’re going out, a measuring stick, measure the ice as you’re walking out.”

The Minnesota Department of Natural Resources (DNR) issued a safety advisory this week, telling ice anglers and others they should stay on shore until there are four inches of measurable new clear ice on a lake surface.   

“There have been quite a few incidents, several incidents in the last few days of people falling through the ice around the state,” noted Nicole Biagi, Ice Safety Coordinator with the DNR.

Authorities say a 16-year-old boy who fell through the ice Monday at Markgraf’s Lake in Woodbury died days later.  

RELATED: 16-year-old boy dies after falling through ice in Woodbury

A 12-year-old, who also fell through, survived and at latest check, is in stable condition.

The DNR says in recent years, there have been between four and six ice-related fatalities in Minnesota.

“Young kids this time of year are very curious about going out,” Biagi explains. “When children wander out onto the ice this time of year, it often ends in tragedy.”

The DNR has guidelines for new, clear ice only:

• 4 inches for ice fishing or walking
• 5-7 inches for a snowmobile or ATV
• 7-8 inches for a side-by-side ATV
• 9-10 inches for a small car or SUV
• 11-12 inches for a medium SUV or small truck
• 13 inches for a medium truck
• 16-17 inches for a heavy-duty truck
• 20-plus inches for a heavy-duty truck with a wheelhouse shelter

Even on the same lake, conditions can vary.

Greg Thomes, Chairman of the Maple Lake Ice Fishing Derby, shared photos with 5 EYEWITNESS NEWS, showing how three-quarters of the lake is covered with ice, but there’s also open water.

“We’re seeing portable ice houses out with 3-5 inches of ice. It’s definitely not any safety there for automobiles or vehicles,” he notes. “We need somewhere around 14-20 inches to host our tournament because of the weight that’s on the ice.”

Thomes says he hopes the ice will thicken by the derby’s opening day next February.  

“We’d like a normal Minnesota winter,” he smiles. “Without the roller-coaster we’ve had with weather the last decade.”

Experts say you should always wear a life jacket or float coat, and carry ice picks, rope, a tape measure and chisel to check ice thickness.

“I usually wait until I know there’s a good enough amount,” says Levi Audette, a 16-year-old ice angler from Brooklyn Park. “I’m anxious to get out. I wear my float suit, I got ice picks around my neck, so if I fall in, I can grab the ice.”

“I just tell people, just stay away from it until you know,” Mitchell adds. “Until you get four, five, six inches.”