Just Ask Us: Lake ice

UW-Madison employee Ray Spiess walks to his office across a frozen Lake Mendota in 2016. Although the Wisconsin Department of Natural Resources has guidelines for judging how safe walking on frozen bodies of water is, it said no ice can ever be 100 percent safe. 

Q: How can I tell if the ice on a lake or river is safe to go out on?

A: No ice can ever be 100 percent safe, according to the Wisconsin Department of Natural Resources.

Ice strength can vary between bodies of water and is based on a combination of factors, according to the DNR. It can’t be judged on a single factor like appearance, age or thickness.

But, if you choose to venture out on a frozen lake or river to ice fish or skate, the ice should be at least two inches thick if you’re venturing out alone, the DNR said. If you’ll be with someone else, the ice should be at least three inches thick.

And if you’re fishing with gear and several other people, at least four inches of ice is needed.

With a snowmobile or all-terrain vehicle, five inches of ice is suggested.

When judging whether ice appears safe or not, look for clear ice, the DNR said. Clear ice is usually stronger than ice with snow or bubbles on it.

In general, river ice is weaker than lake ice, according to the DNR. Other areas where ice could be more dangerous include inlets, outlets and narrows, where currents could weaken the ice.

The best way to gauge how safe the ice might be or where thin spots might be would be to check with local bait shops, resort owners or outdoor stores, the DNR said.

You also can carry devices — ice claws, picks or strong nails — to help pull yourself out of the water if the ice breaks under you and you fall in, according to the DNR.

— Chris Aadland

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