The deadliest winters this century saw 10 people die on the ice in 2002-03 and eight people die in the winter of 2006-07.

The DNR says that 4 inches is the absolute minimum it recommends to walk and fish on new, clear ice. Double that for white or snow-covered ice. But the agency stresses that even following the guidelines there is no certainty.

"You can't judge the strength of ice just by its appearance, age, thickness, temperature, or whether or not the ice is covered with snow," according to the DNR. "Strength is based on all these factors — plus the depth of water under the ice, size of the water body, water chemistry and currents, the distribution of the load on the ice, and local climatic conditions."

The agency is urging parents to teach children about ice safety as thickness increases and many look forward to getting out on the ice.

"Ice, especially early ice with snow cover, is extremely deceptive because you can't see dangerous cracks or the thickness of the ice under the snow," DNR Conservation Officer Adam Block said in a news release. "Parents need to teach their kids that ice is never 100 percent safe. If your child is near the ice, you should be near your child."

The DNR offers the following guidelines for ice safety:

• Always wear a life jacket on the ice (except when in a vehicle).
• Children should never be unsupervised around ice.
• Caution children to stay off ponds, streams, and other bodies of water.
• A thin coating of ice on a pond or lake does not mean it is safe.
• Check ice thickness at regular intervals — conditions can change quickly.
• Before heading out, inquire about conditions and known hazards with local experts.
• Avoid channels and rivers.

The minimum ice thickness guidelines for new, clear ice are:

• 4 inches for ice fishing or other activities on foot.
• 5-7 inches for a snowmobile or all-terrain vehicle.
• 8-12 inches for a car or small pickup.
• 12-15 inches for a medium truck.
• Double these minimums for white or ice covered with heavy snow.