How Lake Ice Melts (2023)

How Lake Ice Melts

How Lake Ice Melts

(Video) Were U Wondering about how lake ice melts? We explain!

After this unusually cold winter and blizzards the past couple weekends, I think we're all ready for the ice to come off the lakes!The last couple weeks we've been in that in-between time when we can't start boating on the lakes because the ice is still on them, but the ice isn't safe to walk on anymore.

The ice went out in southwest and south central Minnesota this past week.This is the latest the ice has stayed on the lakes in southern Minnesotasince 2001. The average date of ice-out for Detroit Lakeis April 20, Lake Sallie is April 18, and Ottertail Lakeis April 15. It looks like this year we will be later than the average.The MN Climatology Working Group has a fun website that tracks the ice cover daily on numerousMinnesotalakes. You can find it here:

(Video) How lake ice really melts.

So how does the lake ice melt?You may have noticed that the ice turned black in some spots and now it looks slushy and opaque. Once the snow melts off the top of the ice, the ice is exposed to the sun.The ice then acts like a greenhouse to the lake water, and as the sun shines on the ice, it heats the water underneath the ice.The ice then starts to melt from the bottom, where it is touching the water. When the ice thickness erodes to between 4 and 12 inches, it transforms into long vertical crystals called "candles." These conduct light well, so the ice starts to look black, because it is not reflecting much sunlight.

As the sun continues to heat the ice, the water below the ice continues to warm. Meltwater fills in between the crystals, which begin breaking apart. The surface appears grayish as the ice reflects a bit more light than before.

(Video) How fast will lake ice melt on a warm day?

Then, all we need is a windy day to break the surface ice apart. The ice candles will often be blown to one side of the lake, making a tinkling sound as they knock against one another, and pile up on the shore. It's amazing how this final process seems to take just a few hours where one day the lake is ice-covered and the next it is not.

Over the next week, the speed of the ice-out process will be dependent on how much sun and wind we get.Only time and the weather will tell how much later than average our ice will go out this year.

(Video) Animation: How a Glacier Melts

I'm already looking forward to sparkling blue water, boat rides and the walleye opener!

Until next week, enjoy the lakes.

(Video) Lake Ice Melt Timelapse

The text about lake ice melting was adapted from Ed Swain, MPCA.

Moriya Rufer is the Lakes Monitoring Program Coordinator for RMB Environmental Laboratories in Detroit Lakes, 218-846-1465,

(Video) How to Use Ice Melt on Sidewalks | Spec. Sense


How quickly does ice on a lake melt? ›

Roughly an inch of surface melting/day is common but rain water is usually too cold to contribute much. Most of the melting is related to warm air. Deep (4-12+") puddles may form as rain water pools and locally depresses the ice sheet.

Where does ice melt first on a lake? ›

Melting. Melting of lake ice usually occurs first near the shorelines or near the mouths of streams. At these points of contact with inflowing warm water, the ice melts faster than it does at central lake locations, where most melting is caused by the transfer of heat from the atmosphere.

Does snow melt ice on a lake? ›

Snow acts much like a blanket, insulating thin ice and preventing the formation of clear, blue ice. Snow can also hide cracked, weak and open water. Daily changes in temperature cause ice to expand and contract, creating cracks and possibly pressure ridges which can affect ice strength.

Does ice get thinner in the middle of the lake? ›

Re: Is lake ice thicker in the middle or close to shore? Ice on the edge is limited to the depth of the water at the edge. So it is always thicker towards the middle.

How many inches of ice is safe on a lake? ›

As a general rule of thumb, ice is safe to walk on when there is 4 inches or more of clear ice. It is important to understand that different types of ice varying in their strength. Clear blue or black ice is the strongest. This ice is formed from the lake water freezing.

How cold is the bottom of a frozen lake? ›

As a result, even in fairly deep lakes the water temperature beneath the ice is usually somewhere below 4° C and quite often closer to 0° C.

Do lakes freeze top down or bottom up? ›

Water freezes from the top down—which allows ice to float—because of a strange quirk in how water's density behaves at falling temperatures.

How long does it take for 4 inches of ice to form on a lake? ›

Ice may form quickly when temperatures tumble, but it takes more time than you might think for ice to reach the four-inch thickness that experts recommend. On average, it takes four days of below freezing temperatures to form ice that is safe. Also, this guideline is for ponds and lakes.

When the lake freezes Where do the fish go? ›

Because warm water sinks in very cold freshwater, fish in these water bodies often gather in groups near the bottom. Some species, like koi and gobies, may burrow into soft sediments and go dormant like frogs and other amphibians, but most fish simply school in the deepest pools and take a "winter rest."

What keeps lakes from freezing? ›

Before a lake can freeze over, its entire water column from top to bottom, must reach that magic temperature (39.2° F or 4° C). This natural cooling process is called fall overturn. It is a gradual process as the surface water slowly cools down and a larger and large layer of water can be mixed by the wind.

Is it colder when you live by a lake? ›

The specific heat of water is higher than any other common substance on Earth. In other words it takes a lot of energy to heat water. The specific heat of land is much lower than water. It varies a little by soil type, but it takes a lot less energy to raise the temperature of the same amount of land as water.

Do lakes ever freeze solid? ›

If water were most dense as a solid, lakes would freeze from the bottom up, eventually freezing solid. In that case, little or nothing would survive in the lake. Most lakes and ponds don't completely freeze because the ice (and eventually snow) on the surface acts to insulate the water below.

Where is the thickest ice on a lake? ›

Lake Vida is one of the largest lakes in the McMurdo Dry Valley region and is a closed-basin endorheic lake. The permanent surface ice on the lake is the thickest non-glacial ice on earth, reaching a depth of at least 21 metres (69 ft).

How do you tell if a lake is frozen enough? ›

General Ice Thickness Guidelines

5 inches or greater The ice should be able to withstand most snowmobiles. 8 and 12 inches The ice should be able to withstand the weight of a small to medium sized car. Anything above 12 inches Ice lakes with this thickness should be able to support medium sized trucks.

Why does lake ice turn black? ›

“Black ice” is ice with fewer, large crystals formed all in alignment, so that the ice is transparent, but looks black because you're able to see the lake beneath it, which between the water and the lake bottom absorb all the light and reflect very little back.

Can you walk on 2 inches of ice? ›

Note that the Army Corps of Engineers says that a person on foot will only need 2 inches of strong ice to be safe (and even a little less than that if you're on skis), but other experts recommend erring on the side of 4 inches.

How long can you survive in a frozen lake? ›

In water that is around the freezing point, a person is likely to survive only 15 to 45 minutes with flotation and possibly up to an hour or so with flotation and protective gear before the brain and heart stop (Table 1).

Is 1 10 inch of ice a lot? ›

Anything under a tenth of an inch is usually considered a glazing, and a quarter-inch or more is usually where you see significant damage. These events may arguably be dreadful, so be prepared and weather-aware and you'll be able to manage the next time some freezing rain comes your way.

Are fish alive in a frozen lake? ›

They survive just fine under the ice,” says Jake Vander Zanden, Director of the University of Wisconsin–Madison Center for Limnology. “They are adapted to survive in these low temperatures; it's not that big of a deal.”

Do fish survive in frozen lakes? ›

The good news is that fish are generally able to adapt to changes in temperature and can survive in cold water for extended periods of time. However, if a body of water freezes over completely and remains frozen for an extended period of time, it is possible that some fish may die.

What happens if you swim in a frozen lake? ›

It can be dangerous, and you can drown,” Packer warned. “The most common source of death from being in cold bodies of water are the cardiac arrests from this cold shock response.” The low temperature also makes the blood pressure rise, leading to fast breathing, and there's a risk of hypothermia.

Why does the middle of a lake freeze first? ›

Water freezes from the perimeter of the lake to the center. It happens this way because the water is shallower at the lake's edge so it cools off faster. Water is most dense at 39 degrees Fahrenheit, so when it gets colder than that, the cold, lighter water floats on top of the lake.

Why does bottom of lake not freeze? ›

The bottom of a lake do not freeze in severe winter. The reason is that ice is a poor conductor of heat hence once the surface is frozen no further heat is liberated or absorbed by water beneath ice. Therefore water below ice never freezes.

What parts of a lake freeze first? ›

Freezing first occurs along the shoreline, where the water is shallow. Before ice can form on the surface, the entire water column must first reach 40 F, which is likely to first occur along the shoreline.

How thick is the ice of a lake to walk? ›

Ice is not considered safe to walk on until it is at least four inches thick. At that thickness, it is suitable for ice fishing, cross country skiing, and walking, and can support about 200 pounds. At five inches, it should be enough to hold a single snowmobile or ATV or about 800 pounds.

How much ice forms on a lake in a day? ›

Based on studies, once a thin layer of ice film forms on a lake, it will add 1 inch of ice for every 15 freezing degree days in a 24 hour period.

Is 2 inches of ice enough? ›

If you're going skating or ice fishing with a group, stay off ice that's less than four inches thick. As a general rule, avoid ice that has cracks or ice near inlets or moving water.

Where do bass go when lakes freeze? ›

They stay in deep waters during winter, occasionally feeding. Bass lose their appetite the colder it is outside. Sometimes these fish hang around the docks, in the deepest part. They use the pilings for warmth and survival as it hides them from predators.

What lake never freezes? ›

Issyk-Kul is a lake without a drain and is located in the northeastern part of the Central Asia nation. It also keeps scientists intrigued as the water of this lake never freezes due to the lake's depth and natural warmth of the water. This is the reason, it was named Issyk-Kul, which means "warm lake" in Kyrgyz.

Why do oceans not freeze? ›

Ocean water freezes at a lower temperature than freshwater.

Ocean water freezes just like freshwater, but at lower temperatures. Fresh water freezes at 32 degrees Fahrenheit but seawater freezes at about 28.4 degrees Fahrenheit , because of the salt in it.

Why are lakes only frozen on top? ›

Right when the water freezes to ice, the ice becomes significantly less dense than the water and continues to float on the lake's surface. Below 4° Celsius, water becomes less dense as it gets colder, causing water about to freeze to float to the top.

Is it healthy to live by a lake? ›

When you live on the lake, you're exposed to clean air, and plenty of it. With less air pollution, there is a noticeable difference in the air quality around a lake. By spending more time in fresh air, you can help boost your immune system and increase your white blood cell count, helping you fight off infections.

Where is the warmest part of a lake? ›

In summer, the top of the lake becomes warmer than the lower layers. You've probably noticed this when swimming in a lake in summer - your shoulders feel like they're in a warm bath while your feet are chilled. Since warm water is less dense that colder water, it stays on top of the lake surface.

What is the coldest part of a lake? ›

The bottom layer is the coldest, staying at around 39–45 degrees F (4.0–7.4 degrees C). Since light does not penetrate to the bottom, photosynthesis is limited to the top layer.

Why does Lake Michigan not freeze? ›

While the Great Lakes will freeze over partially during the winter, they almost never freeze completely. This is mainly due to their size. The Great Lakes are too large to freeze over entirely on a regular basis.

Do the Great Lakes have sharks? ›

The water temperature in the Great Lakes is far too cold for most sharks (including the Bull Shark). Even if it managed to make it through the summer months, our frigid winters would turn it into a “sharksicle” in no time.

Are US lakes drying up? ›

As watersheds receive less rain and snowpack, reservoirs and natural lakes across the region are drying up. Let's take a look at 5 lakes in the U.S. that have almost dried up in 2022's heat.

Where is 90% of all ice found? ›

At its thickest point the ice sheet is 4,776 meters deep. It averages 2,160 meters thick, making Antarctica the highest continent. This ice is 90 percent of all the world's ice and 70 percent of all the world's fresh water.

Where is 90% of Earth's ice found? ›

Ice caps around the world

The vast majority, almost 90 percent, of Earth's ice mass is in Antarctica, while the Greenland ice cap contains 10 percent of the total global ice mass.

How much weight will 4 inches of ice hold? ›

Do not attempt to stand or walk on ice that is less than four inches thick. Ice fishing can be safely completed on ice that is four inches or thicker. Four inches of ice can hold roughly 200lbs.

Can you drink water from a frozen lake? ›

Either boil or chemically treat raw water - do not directly eat snow or ice because it can be contaminated with bacteria.

How thick does ice freeze on a lake? ›

Ice between about 30 cm and 70 cm on a cottage-country lake is not unexpected under average freezing conditions. But there's no maximum; in the Northwest Territories, lake ice can become several metres thick. Of course, ice thickness anywhere varies from year to year depending on—no surprise—air temperature.

Does rain help melt lake ice? ›

Rain has relatively little effect on ice. An inch of rain falling in 40 degree air temps has enough thermal energy to melt about 1/16" of ice. The wind that often accompanies rain accounts for most of the thickness loss of an ice sheet in a storm.

Does the sun melt black ice? ›

Black ice (or packed snow) reflects the sun. It won't absorb solar energy so it can't evaporate. It may remain a hazard all winter.

Why does lake ice moan? ›

For a round lake of about a mile across, warming 20° F would expand the ice sheet by about four feet. That expansion causes the ice to crack and deform and this causes vibration of the ice that you hear as sounds. Likewise, when it cools again it will contract, crack and deform making similar sounds.

How fast does a lake freeze at 15 degrees? ›

Based on studies, once a thin layer of ice film forms on a lake, it will add 1 inch of ice for every 15 freezing degree days in a 24 hour period.

Will ice melt work at 25 degrees? ›

Some ice melt is effective at temperatures as low as -25 degrees F. Some will only work down to 25 degrees F. In extremely cold temperatures, exothermic ice melt which releases its own heat will be more effective because it produces moisture, allowing brine to form and penetrate the ice.

Can an entire lake freeze? ›

Before a lake can freeze over, its entire water column from top to bottom, must reach that magic temperature (39.2° F or 4° C). This natural cooling process is called fall overturn. It is a gradual process as the surface water slowly cools down and a larger and large layer of water can be mixed by the wind.

Will rain wash away ice melt? ›

Rain will wash away the liquid ice melt that has been applied to the surface. This includes forecasted freezing rain that is anticipated before or during a snowstorm.

Does ice melt faster in sun or shade? ›

The ice cube in the sun will melt faster because it absorbs the heat energy from the sun.

What will instantly melt ice? ›

If you're looking for the fastest ice melt, salt is usually a clear winner. Why does salt melt ice? It works by lowering the freezing point of water molecules, or the freezing point depression. Rock salt is a great way to melt ice, but it can be pricey and bad for the environment.

Why should you not walk on a frozen lake? ›

Depending on the thickness of the ice, there may be limitations on what you can do on its surface. 2 inches thick The ice is very susceptible to breakage and is not safe to walk on. 4 inches thick It should be ok to stand, skate, and ice fish on the surface.


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6. How to make your own ice melt
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