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How to have fun safely on the ice

January 12, 2025  |  Topics: Stories

By Craig Mattson, Schlitz Audubon Nature Center

Photography by Eddee Daniel

Note: The photographs that accompany this story are from a variety of parks as indicated in the captions. Links in the captions will take you to our Find-a-Park pages so that you can learn more about the parks if you wish.

Ice is one of the most beautiful sights of the winter season, be it the sheen on the surface of a pond or intricate ice formations. It is often a place to walk and travel on, too. If you’re planning to explore, play, fish, or otherwise traverse the icy surface of a water body, there are a few precautions you should take to help ensure safety on the ice.

The Urban Ecology Center's Winterfest brings crowds to the Washington Park lagoon for ice skating.
The Urban Ecology Center’s Winterfest brings crowds to the Washington Park lagoon in Milwaukee for ice skating.

Three Conditions to Avoid

One thing to consider is the types of ice to avoid. There are three dangerous conditions that you should be aware of. One is ice located on the surface of moving water, such as a river. Moving water doesn’t freeze evenly, leading to thin patches.

Moving water, such as these rapids on the Menomonee River in Hoyt Park, can make for treacherous ice conditions.
Moving water, such as these rapids on the Menomonee River in Hoyt Park, Wauwatosa, can make for treacherous conditions.

The second condition is seen in large bodies of water, such as Lake Michigan. Because of its size, Lake Michigan remains slightly warmer and doesn’t freeze as evenly as a smaller water body. In fact, Lake Michigan never fully freezes. Ice that can look solid is often unpredictable in its strength. The ice shelf that forms at the Center’s Lake Michigan shoreline should be approached with caution for these reasons.

These ice shelves along the shore of Lake Michigan at Schlitz Audubon Nature Center (and elsewhere) are uneven in thickness and unstable due to constant wave action.

The third condition to be aware of is water by a spring. You can tell where these are by a raised hill-like area near the shore. These often indicate spring activity. Springs promote water movement, which can weaken the surface ice.

A small mammal walked across this buckling ice shelf at Scuppernong Springs in the Southern Unit of the Kettle Moraine State Forest, but it wouldn't hold my weight. The relatively warm spring water keeps the Scuppernong Creek fed by these springs open and ice-free.
A small mammal walked across this buckling ice shelf at Scuppernong Springs in the Southern Unit of the Kettle Moraine State Forest, but it wouldn’t hold my weight. The relatively warm spring water keeps the Scuppernong Creek fed by these springs free-flowing and ice-free.

Ways to Gauge Ice Safety

Once you are mindful of these three dangerous areas, there are ways to make sure that any ice you want to travel on is strong enough. One thing to keep in mind is that it’s difficult to judge the thickness of any ice by sight. Light refracts on the surface, making the ice look thinner than it is. There are simple tools that will help you gauge the thickness of the ice, such as an ice pick and a nail. Simply tap the nail into the surface, waiting to see where it breaks through the bottom layer, and make note of the thickness at that point.

A section of the Humboldt Park lagoon cleared for hockey games.
A section of the Humboldt Park lagoon in Bay View cleared for hockey games.

If you have access to larger equipment, you might also use a drill to bore into the ice, or even an augur. These are quick ways to see how thick the ice is, but require some more planning, and will have you carrying more weight onto the ice.

Using a drill to determine the thickness of the ice. Photo courtesy Schlitz Audubon Nature Center.
Using a drill to determine the thickness of the ice. Photo courtesy Schlitz Audubon Nature Center.
Using an ice auger to make a hole for fishing at Ottawa Lake State Recreation Area.
Using an ice auger to make a hole for fishing at Ottawa Lake State Recreation Area.

Once Naturalists at the Center know the thickness of the ice from using an ice pick and nail, they will slowly test it by first stepping onto the ice with one foot, then adding their full weight. Once they know their full weight will hold, Naturalists will begin to shift a little on the surface, then kick the ice to ensure it is strong enough to hold them and their students.

An ice fisherman carrying an ice auger between ice shanties at Lakeshore State Park.
An ice fisherman carrying an ice auger between ice shanties at Lakeshore State Park in Milwaukee.

You can use an ice safety thickness chart to determine if the ice is thick enough to walk on. There are many sources of ice safety information, and many organizations suggest different thresholds for thickness. One of them is the Farmer’s Almanac. It recommends the ice be three inches thick for one person to stand on it, and four inches for a group in single file. A two-ton car will need 7.5 inches. Other sources to consider include ice safety charts from the Army Corps of Engineers and the Minnesota DNR [or the Maine Lakes Environmental Association, below].

Courtesy Maine Lakes Environmental Association
A snowmobile on the ice of the Milwaukee River at Shoreland Nature Preserve in Mequon.
A snowmobile on the ice of the Milwaukee River at Shoreland Nature Preserve in Mequon.

Surface and Ice Conditions

Consider the kind of ice you encounter. Knowing areas of the ice’s surface that are weaker will help you avoid accidents. Clear ice, also called black ice, is the strongest. White or hazy ice, caused by slush or snow mixing with the ice when it was formed, is half as strong as clear ice. If the area you are walking on has white ice, make sure there is also enough clear ice beneath it to hold your weight.

Ice broken up by freezing, thawing and refreezing, which causes very unstable, dangerous conditions.
Ice broken up by freezing, thawing and refreezing, which causes very unstable, dangerous conditions. Milwaukee River at Kletzsch Park, Glendale.

Also, be aware of the area near the edge of the water, where snow can accumulate. This insulates the water from freezing. Another thing to watch for is plant material on the surface, where there may be dark areas at the point where the object meets the surface. The dark areas attract sunlight, melting the ice.

This man thought he was jumping over open water onto solid ice. I caught him as he broke through the thinner ice at the edge. Luckily for him the water was not deep right there. Kettle Moraine State Forest - Pike Lake Unit.
This man thought he was jumping over open water onto solid ice. I caught him as he broke through the thinner ice at the edge. Luckily for him the water was not deep right there. Kettle Moraine State Forest – Pike Lake Unit.

The right kind of ice is safer than you might think. Fluctuating temperatures have less of an effect on thickness because water has a high specific heat, which means it takes a lot of energy to make water change state from solid to liquid. Ice is slow to respond when the temperature gets warmer.

Cracks (and bubbles) in clear ice can reveal how thick the ice is. This ice on the lagoon at Greenfield Park in West Allis was at least four inches thick. The sound of the ice cracking can be unnerving, but when it's this thick it remains stable.
Cracks (and bubbles) in clear ice can reveal how thick the ice is. This ice on the lagoon at Greenfield Park in West Allis was at least 4-5 inches thick. I have to admit, however, that the sound of the ice cracking can be unnerving.

Water naturally expands when it freezes, and you will often hear the sound of this when it happens. Be very cautious when the ice cracks, especially with snow-covered ice. However, the cracking sound this makes does not necessarily signal danger. Ice is flexible, so it bends with people’s weight. When the ice thickness is determined to be safe, small fluctuations on the surface are usually slow to have an effect. When in doubt, stay off cracking ice.

Skating on a cleared section of the Milwaukee River at Pleasant Valley Park in the Milwaukee River Greenway.
Skating on a cleared section of the Milwaukee River at Pleasant Valley Park in the Milwaukee River Greenway.

These easy to follow safety steps will help you have a good time doing any activity on the ice. If possible, have a buddy system in place, too. When you’re on the ice with a group of people, they can watch out for one another. Knowing effective safety precautions will help you to keep your peace of mind, allowing you to enjoy your time outdoors.

Approximately 75 people participating in the annual "Bog Walk" at the Cedarburg Bog State Natural Area in Saukville walk down the center of a frozen creek. They were warned not to stray too close to the vegetation, which keeps the water from freezing solid.
Approximately 75 people participating in the annual “Bog Walk” at the Cedarburg Bog State Natural Area in Saukville walk down the center of a frozen creek. They were warned not to stray too close to the vegetation, which keeps the water from freezing solid.
Fishing with multiple holes drilled with an ice auger. Milwaukee River Greenway at North Avenue. The holes are an obvious way to measure the depth of the ice.
The same fishermen, above, showing their proximity to open water where the faster current keeps the river from freezing, under the North Avenue bridge.
The same fishermen, above, showing their proximity to open water where the faster current keeps the river from freezing, under the North Avenue bridge.
An "erupting" ice-cano on the shore of Lake Michigan in Big Bay Park.
“Ice-canos” like this one on the shore of Lake Michigan in Big Bay Park in Whitefish Bay can be a big draw, but don’t get too close!
A fat-tire mountain biker plows through fresh snow on the Milwaukee River at Cambridge Woods in the Greenway. Take extra precautions with snow-covered ice as it's hard to determine the depth and condition.
A fat-tire mountain biker plows through fresh snow on the Milwaukee River at Cambridge Woods in the Greenway. Take extra precautions with snow-covered ice as it’s hard to determine the depth and condition.
A Milwaukee Fire Dept. rescue team practicing water rescue on the frozen Milwaukee River at the Third Ward in Milwaukee.
A Milwaukee Fire Dept. rescue team practicing water rescue on the frozen Milwaukee River at the Third Ward in Milwaukee.

Note on photography below: I was inspired by this article to go to Greenfield Park when the ice was still clear. While most people think of going on ice for active sports like skating, hockey, and other things pictured above, what I like to do is find interesting things to photograph in the ice itself. This is a selection. ~ Eddee

Bubbles frozen in place in the ice create a galaxy-like pattern.
Air bubbles frozen in place in the ice create a galaxy-like pattern.
The patterns of fallen tamarack needles remind me of Chinese screen paintings. (Tamaracks are a deciduous conifer, dropping their needles in the fall.)
The patterns of fallen tamarack needles remind me of Chinese screen paintings. (Tamaracks are a deciduous conifer, dropping their needles in the fall.)
Bubbles and a fallen birch timber in the ice.
Bubbles and a fallen birch timber in the ice.
Now and then I saw fish swimming under the ice.
Now and then I saw fish swimming under the ice.

For more information about ice safety go to the Farmer’s Almanac website.

Related stories:

Walking on the River!

A Walk in the Wilderness of Cedarburg Bog!

Winter is Lake Michigan’s showiest and finest hour

Winter Waterfalls: Manitowoc and Brown Counties

Winter fun all over SE Wisconsin!

Craig Mattson was a Communications Specialist at Schlitz Audubon Nature Center when he wrote this story. This story originally appeared without the photos in the Schlitz Audubon Nature Center blog. It is reprinted here with permission. The photo at the top of the boy testing the ice on a river is from the Menomonee River Parkway in Wauwatosa. All photos by Eddee Daniel, except as noted. Eddee Daniel is a board member of Preserve Our Parks and a member of Schlitz Audubon Nature Center, which is also a project partner of A Wealth of Nature.

2 thoughts on "How to have fun safely on the ice"

  1. Dave Bishop says:
    January 13, 2025 at 9:20 am

    I fell through the ice on the Milwaukee River when I was around nine years old. I had to walk home through fields for over a mile. Needless to say, I was terrified, and my snowsuit was frozen solid when I got home. I don’t go out on ice much anymore.

  2. Eddee says:
    January 13, 2025 at 11:29 am

    Thanks for the cautionary note, Dave! I have fallen through ice myself (though not at an impressionable early age). The first rule is not to venture onto ice alone. The second is to determine that it is safe as mentioned in the story. Eddee

Comments are closed.