Even then, don t assume that thick ice is safe ice because there are a lot of variables involved in how strong ice is, and ice can be very unpredictable. The DNR never certifies ice as being safe for travel due to constantly changing conditions. Ice bends up and down in long waves that roll away from a car as it drives across the ice. Because of this wave action, drivers who are taking their cars or trucks onto the ice shouldn t follow closely behind other cars or they could cause a breakthrough on otherwise safe ice, Thoresen said, and even thick ice may crack if a car drives above a certain speed on it. New ice is much stronger than old ice, as is ice formed when the lake freezes instead of ice that forms when snow melts and freezes.
Clear ice is generally stronger than ice with air bubbles in it.
Check the ice from shore before you go out, and check it frequently as you move around. Do not allow children on the ice without adult supervision. Also check for local ordinances that may prohibit vehicles from traveling on ice or require vehicles to be equipped with flotation. Wear proper clothing and equipment, including a float coat. An ordinary nylon snowmobile suit will trap air and slow your body's heat loss.