Ice Safety: Walking and Skating on Frozen Lakes

A frozen Swedish lake invites you to walk straight out onto it, and on a clear winter day half the town seems to be out there. Nobody checks natural ice for you, though. Here is what Sweden’s ice-safety council says before you step off the shore.

When you need this

You want to walk, ski or skate on a frozen lake, go ice fishing, or cross the ice on a snowmobile. Maybe you’re travelling with children or a dog and wondering how close to the edge is too close. Or you’ve seen people far out on the ice and want to know whether it’s safe to follow them. It isn’t, on that evidence alone: Issäkerhetsrådet warns that people regularly go through while following others’ tracks.

Outside a few ploughed skating tracks and the state’s official ice roads, every trip onto natural ice rests on your own judgment. The advice below comes from Issäkerhetsrådet, the ice-safety council. Its members include Svenska Livräddningssällskapet (the lifesaving society), the snowmobile federation, Friluftsfrämjandet, Sjöräddningssällskapet (the sea rescue society), the skating clubs and the anglers’ association.

Clear ice and snow ice

Ice is not one material, and the kind you’re standing on changes what its thickness means.

Snow on the ice hides weaknesses and insulates the ice, so it grows more slowly. Under thick drifts it can be almost melted away. Grey slushy patches in the snow suggest the ice is being eaten away from below. Dark areas usually mean thinner ice. In soft shoes you can walk a long way onto weak ice without feeling anything.

How thick is thick enough

Issäkerhetsrådet publishes one figure: clear core ice should be at least 10 cm thick before you go on it. For ice fishing it gives the same measure, “at least one decimetre of core ice”. Everything else is described, not measured. Sweden’s safety council publishes no per-activity thickness table, and neither do we.

Treat 10 cm as a minimum, not a guarantee: it refers to core ice, and snow ice bears less. Skis spread your weight, so they carry you far onto ice that would stop a walker. They also make it almost impossible to climb out, because many bindings cannot be released in the water. On a snowmobile, engine noise hides the ice’s warning sounds, and speed carries you far onto weak ice before it breaks.

The one place where someone else checks the ice for vehicles is Trafikverket’s ice roads (isvägar). These are winter roads that replace or supplement some road ferries. They open only when the ice bears at least two tonnes, and staff measure it about every 25 m.

Where ice is weak

Ice can change within metres. Even after a week or more of cold, Issäkerhetsrådet says currents keep ice weak in predictable places, and it explains why:

• Stream inlets and outlets: moving water brings warmer water to the surface, sometimes a long way out.
• Straits, shallows and points: water squeezes through and mixes warmer bottom water upward.
• Reeds: the stems conduct heat from the lake bed.
• Under bridges and jetties: they act as a roof and stop the ice cooling.
• Sewage outlets: warm water rises.
• Cracks and pressure ridges (råkar): a ridge covered by thin new ice and snow is a trap.
• Vindbrunnar: patches that stayed open after the rest froze, then iced over late.

Rivers and regulated waters have thinner ice, and crossings that were “safe” can change fast. In the north, ice is often snow-covered and over half a metre thick, but currents, wind cracks and spring thaw still catch people. In the south it is thinner and more often clear. Smaller lakes freeze earlier and often have safer ice than big ones, where strong wind can break it up.

Sea ice and the archipelago

Issäkerhetsrådet is blunt: sea ice is always weaker than lake ice, because salt makes it less strong. It gives no clear warning sound as it thins, it’s harder to judge with a pole, and wind, waves and boats can break it up and set it drifting.

That includes the Baltic. SMHI, the weather and water agency, describes the Baltic as brackish, with surface salinity around 7. Skagerrak on the west coast is almost oceanic, and the northern Bothnian Bay is almost fresh. So Stockholm’s archipelago ice is sea ice, not lake ice. Ferries and ships also break channels (isrännor) through it, sometimes at short notice. Go out there only with experienced company or a guide. Skaters should read our Nordic ice skating guide.

What to carry

On uncontrolled ice, Issäkerhetsrådet’s kit for walkers is the same as for skaters off prepared tracks.

Walking on clear ice is also slippery: Issäkerhetsrådet says it is often too slippery to walk on comfortably without shoe cleats (broddar). Go with company, never alone, and tell someone where you’re going and when you’ll be back. In spring, plan a safe way back to shore, preferably to a shaded one. Ice near land weakens first, sometimes in 15–20 minutes once the sun gets on it.

If you go through

The first danger is not the cold. Sjöräddningssällskapet warns that the gasp reflex can drown you within a couple of seconds. Then Issäkerhetsrådet’s steps:

1. Get through the shock: face above water, get your breathing under control. You have many minutes before the cold stops you acting.
2. Turn back the way you came. The ice held there.
3. Take out your ice claws with your gloves on, keep your elbows close to your body, and work steadily onto firm ice.
4. Crawl well away before you stand up.
5. If help is coming, lie still to save strength.

Don’t try to swim for a distant shore. Once out, get dry and warm; our cold safety guide covers hypothermia first aid.

Helping someone else

1. Call 112 first, as early as possible. It’s free and works without a SIM.
2. Approach from the direction they came from.
3. Always keep something between you and them: a throw line, an ice pole, a branch or a jacket. A helper who ends up in a second hole makes things worse.
4. Once they’re out, get them dry and insulated. 1177, the health advice service, says anyone pulled from cold water needs a hospital check, even if they seem fine.

Children and dogs

Children on the ice need at least one adult with them, and children who cannot swim should wear a rescue life jacket. Let them practise with ice claws and a throw line before going out. Spruce branches or tape on posts out on the ice usually mark a hole someone has cut for bathing or fishing. Whoever cuts one is expected to mark it, so keep children well clear.

A loose dog can run onto ice that won’t hold its owner. Issäkerhetsrådet recommends keeping dogs on a lead on or near ice. If a dog goes through, call 112 and wait for the rescue service: going after it yourself can cost you your life. For the legal leash season, see dogs in Swedish nature.

Mistakes to avoid

• Following other people’s tracks. Their presence proves nothing.
• Trusting snow-covered ice because it looks solid.
• Testing with a ski pole. Too light to tell you anything.
• Packing the throw line inside the backpack, out of reach once you’re in the water.
• Confusing “ice picks”. In English it usually means the claws (isdubbar); the Swedish ispik is the long pole.
• Looking for Stockholm’s ice thickness online. The city doesn’t report it for its ploughed tracks.

Practical information

FAQ

How thick does ice need to be to walk on in Sweden?

Issäkerhetsrådet, the Swedish ice-safety council, says clear core ice should be at least 10 cm thick. That is its only published figure for people on foot, and it uses the same one decimetre for ice fishing. Snow ice bears less than core ice, and sea ice is always weaker than lake ice, so treat 10 cm as a minimum, not a guarantee.

How thick must ice be for a snowmobile or a car?

Issäkerhetsrådet says a snowmobile needs thicker ice than a skier but gives no figure, and it publishes none for cars. Trafikverket’s official ice roads open only when the ice bears at least two tonnes, and each road shows its own weight limit. On an ordinary lake no one checks, and a driver who goes through pays for the rescue.

What should I do if I fall through the ice?

Get your breathing under control first. Turn back the way you came, because the ice held there. Take out your ice claws, work steadily onto firm ice, lever yourself up with your elbows close to your body and crawl well away before standing. If help is on its way, lie still to save strength. Then warm up and get dry.

How do I help someone who has fallen through the ice?

Call 112 at once. Approach from the direction they came, and never go out without something between you and them — a throw line, an ice pole, a branch or a jacket. A helper who ends up in a second hole makes things worse. Anyone pulled from cold water needs a hospital check, even if they seem fine.

Is sea ice in the archipelago safe to walk on?

It is riskier than lake ice. Issäkerhetsrådet says salt makes sea ice always weaker; it gives no clear warning sound, is harder to test and can break up in wind, waves or boat traffic. The Baltic is brackish, so its ice counts as sea ice. Ferries break channels at short notice. Go only with experienced company or a guide.

Can children go out on the ice?

Yes, with care. Issäkerhetsrådet says children on the ice must have at least one adult with them, and children who cannot swim should wear a rescue life jacket. Let them practise with ice claws and a throw line first. Keep them away from reeds, jetties, stream mouths and any marked hole in the ice.

Where can I check ice conditions before going out?

There is no national ice-thickness service for lakes. SMHI publishes an ice chart for the sea, Vänern and Mälaren, but warns it is a general analysis. Trafikverket’s traffic map shows whether its ice roads are open. Stockholm publishes no thickness for its ploughed tracks. In the end you test the ice yourself with an ice pole.

Related guides

• Ice skating on natural ice: tracks, tours and the kit skaters carry
• Ice fishing in Sweden: fishing rules on the ice, and driving on lake ice
• Cold risks: hypothermia and frostbite: first aid once someone is out of the water
• Cold baths and winter bathing: dipping in an ice hole safely
• Emergency numbers in Sweden: 112 and when to call it

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Facts verified 2026-09-25. Sources: Issäkerhetsrådet, Trafikverket, SMHI, the City of Stockholm, Sjöräddningssällskapet, 1177, SOS Alarm and Ludvika municipality. The full register is in this topic’s source file. No current ice status is published here, so test the ice yourself on the day. Found something outdated? Tell us and we’ll fix it.