When is it safe to ride onto the ice? The Minn. DNR has posted guidelines on its' website suggesting 5-inches of ice thickness for snowmobiles.
Before heading out on the ice the DNR suggests contacting a local bait shop or lakeside resort to ask about ice conditions.
Then check ice conditions once you get to the water.
Temperature, snow cover, currents, springs and rough fish all affect the relative safety of ice. Ice is seldom the same thickness over a single body of water; it can be two feet thick in one place and one inch thick a few yards away. Check the ice at least every 150 feet, according to the DNR.
Ice thickness can be checked using an ice chisel, ice auger, cordless drill or tape measure.
An ice chisel is a 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.
There are 3 different kinds of augers: hand, electric and gas. Hand augers are low cost, light weight and quiet. Electric augers are also quiet, but use less manual labor than a hand auger. Gas augers drill through ice the fastes, but are heavier, noisier and generally more costly than hand or electric models. After drilling a hole with the ice auger, measure ice thickness with a tape measure.
Using a cordless drill and a long, five-eighths inch wood auger bit, you can drill through eight 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 measure tape. Dry the bit and give it a quick spray of silicone lubricant after each use to prevent rust.
Use a tape measure to find ice’s true thickness. Put the tape measure into the hole and hook the bottom edge of ice before taking measurement. You can also use an ice fisherman'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.
Cars, pickups or SUVs should be parked at least 50 feet apart and moved every two hours to prevent sinking.
Make a hole next to the car. If water starts to overflow the top of the hole - the ice is sinking and it’s time to move the vehicle.