Ice is never 100% safe. There are many factors besides thickness that affect ice strength. It’s important you understand all the factors that could create hazardous ice and have the appropriate safety gear before you begin measuring ice thickness.
Once you have the proper safety gear, grab a tape measure and one of the other tools below to measure ice thickness. Wait for at least 4 inches of new, clear ice before you consider walking out.
Ice chisel
An ice chisel or spud bar is a heavy metal rod with a sharp, flat blade welded onto one end. Drive the chisel into the ice, using a stabbing motion, to create a hole. Next, measure ice thickness with a tape measure.
Ice chisels are an especially important tool in the early and late-ice season when the ice is not as thick as mid-winter. If you are walking on 4 to 6 inches of ice, you likely will find areas of ice that are less than 4 inches on the same lake. With the chisel, you can stab the ice in front of you with each step you take to ensure the ice has not suddenly become thinner.
Checking as you walk with an ice chisel is not a substitute for measuring ice frequently with a tape measure.
Ice auger
There are three different kinds of augers: hand, electric and gas. Anglers commonly use augers to drill holes for fishing, but they also can be used for measuring ice thickness. After drilling a hole with the auger, measure ice thickness with a tape measure. If you are using an auger to check ice thickness, make sure to start by checking thickness near shore and to frequently stop and check as you go.
Cordless drill
Using a cordless drill and a long, 5/8-inch wood auger bit, you can drill through 8 inches of ice in less than 30 seconds. Most cordless drills that are at least 7.2 volts will work, but the type of bit is critical. You need a wood auger bit since they have a spiral called a “flute” around the shaft that metal drilling bits don’t. The flutes pull the ice chips out of the hole and help keep it from getting stuck, much in the way a full-sized ice auger works. After drilling a hole, measure ice thickness with a tape measure. Dry the bit and give it a quick spray of silicone lubricant after each use to prevent rust.
Tape measure
Use a tape measure to accurately measure ice thickness. Put the tape measure into the hole and hook the bottom edge of the ice before taking measurement. You can also use an ice angler’s ice skimmer with inch markings on the handle in place of the tape measure.
Don’t judge ice thickness by how easily a chisel or drill breaks the surface. It happens so quickly that it’s easy to overestimate the thickness.