The North Dakota Game and Fish Department is urging winter anglers and late-season hunters to use extreme caution when venturing out on ice.

Ice thickness is never consistent, especially early in winter, and can vary significantly on the same body of water. Edges become firm before the center.

A few reminders include:

• Snow insulates ice, which in turn inhibits solid ice formation, and hides cracks, weak and open water areas.
• Avoid cracks, pressure ridges, slushy or darker areas that signal thinner ice. The same goes for ice that forms around partially submerged trees, brush, embankments or other structures.
• Ice thickness is not consistent and can vary significantly even in a small area. Ice shouldn’t be judged by appearance alone. Anglers should drill test holes as they make their way out on the lake, and an ice chisel should be used to check ice thickness while moving around.
• Daily temperature changes cause ice to expand and contract, affecting its strength.
• The following minimums are recommended for travel on clear-blue lake ice formed under ideal conditions. However, early in the winter it’s a good idea to double these figures to be safe: 4 inches for a group walking single file; 6 inches for a snowmobile or all-terrain vehicle; 8-12 inches for an automobile; and 12-15 inches for a pickup/truck.

These tips could help save a life:

• Wear a personal flotation device and carry a cell phone.
• Carry ice picks or a set of screwdrivers to pull yourself back on the ice if you fall through.
• If someone breaks through the ice, call 911 immediately. Rescue attempts should employ a long pole, board, rope, blanket or snowmobile suit. If that’s not possible, throw the victim a life jacket, empty water jug or other buoyant object. Go to the victim as a last resort, but do this by forming a human chain where rescuers lie on the ice with each person holding the feet of the person in front.
• To treat hypothermia, replace wet clothing with dry clothing and immediately transport victim to a hospital.