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Wentzville Fire Protection District firefighter and fire truck at a fire training exercise

Wentzville FPD News & Fire Safety Tips

Frozen Fears: Learn the Importance of Water and Ice Safety During Winter

Nearly every year in Missouri, a fall through an ice-glazed body of water leads to injury or death. In 2022, two individuals fell through ice-covered Creve Coeur Lake; the duo suffered no injuries (thanks to first responders). While walking across a seemingly solid body of water might seem like a fun shortcut or an ideal makeshift ice rink, that sheet of ice is likely deceiving. 

Frozen lakes and ponds are not for crossing. The mass of an upright individual is typically far greater than the ice can support. Know the dangers of frozen lakes and ponds; here is what to know about water and ice safety during winter.

Table of Contents:

Ice Thickness Safety

Ice Safety Chart

Ice Safety Tips

  • What is the First Stage of Cold Water Immersion?

  • How Do You Assume the Help Position to Reduce Heat Loss in Cold Water?

Cold Water Safety

FAQ: Ice and Cold Water Safety

Key Takeaways:

A layer of ice on a frozen pond or lake must be at least four inches thick to support the weight of an individual. Never assume a frozen body of water is safe, and do not attempt to cross frozen surfaces. Parents also must always supervise children around any body of water (frozen or unfrozen).

Ice Thickness Safety

Parents must teach their children that frozen lakes and ponds pose a life-threatening hazard. Many children see a frozen lake or small pond covered with snow and assume it’s a convenient DIY ice rink for playing games and sliding like an ice skater (or hockey player). While the body of water is frozen and snow-covered, it’s impossible to discern the thickness of the ice throughout the entire span of the pond or lake.

One step onto the ice might feel fine. A child keeps walking further out, only to discover that the ice is now cracking and crumbling. Suddenly, that once-solid layer of ice cracks and breaks apart beneath their feet. The cold water then engulfs them. 

This is the most likely scenario when a child ventures onto a frozen pond (or lake). While some lakes freeze solid and transform into ice rinks, only a professional knows when a lake or pond is safe for skating and playing.

The thickness of the ice can vary throughout a body of water. In some areas, the ice layer is incredibly thin, unstable, and cannot support much weight. So, how thick does the ice need to be to support the weight of most individuals properly? The magic number is…FOUR INCHES! 

Any section of ice less than four inches thick will likely collapse beneath an individual’s feet. This is how winter drownings and hypothermia occur. Depending on the temperature of the water, hypothermia can begin in mere minutes. Death from hypothermia can occur in less than 20 minutes. 

Never ever risk a fall through the ice. Don’t attempt to walk on or cross frozen bodies of water! 

Ice Safety Chart

Ice four inches thick can support walking and the weight of a human. In addition, extremely cold temperatures freeze water far beneath the surface; this results in extremely thick ice sheets that can handle the weight of vehicles! Use our ice safety chart to understand the correlation between ice thickness and other the activities the ice supports:



Less than 4”

No activity is safe on sheets of ice less than four inches thick! Stay off the ice!


Ice that is at least 4” thick supports walking, ice fishing, and ice skating. 


The ice can support snowmobiles and the weight of numerous individuals.

6” to One Foot

Cars and trucks can drive across the ice (be careful when navigating, though)

Thicker than 12” 

SUVs and larger trucks safely navigate the ice. The show Ice Road Truckers documents truckers whose jobs require them to navigate across frozen bodies of water.

How to Measure Ice Thickness

An individual cannot measure or guestimate ice thickness simply by sight. Measuring ice thickness requires an individual to chisel through the ice to evaluate the thickness; typically, a tape measure is used for proper assessment. The individual crosses the ice at a small section at a time, and only a professional should handle ice measurements. 

In Missouri, it is not incredibly common for local ponds or lakes to accrue a layer of ice substantial enough to support the weight of an individual. The days and nights must be consistently below freezing for water to solidify a four or more inches thick sheet of ice.  

The Missouri Department of Public Safety Office of the Fire Marshall advises parents always to supervise children near ice. Children also should wear a life jacket near frozen bodies of water (in case the ice breaks beneath them). The Department explains that 'white ice' is extremely dangerous; this is due to snow mixing with ice and creating air pockets, making the ice delicate. River ice is NEVER SAFE.

Ice Safety Tips

Ice-covered bodies of water look like an ideal space for winter games and fun. However, children and adults must assume that all frozen surfaces are fragile and cannot hold their weight. 

Never attempt to walk on a frozen pond or lake. What happens, though, if an individual ventures onto the ice and falls through the ice layer? Extremely cold water can lead to hypothermia in a matter of minutes, and knowing how to manage this emergency can save a life. The Department of Public Safety advises that when an individual falls through the ice, call 911 immediately. 

Attempting a rescue could lead to another individual falling into the water; however, the Department recommends throwing a rope, jumper cables, or a ladder to help pull the individual to safety.

What is the First Stage of Cold Water Immersion?

When an individual falls through the ice and into extremely cold water, the body exhibits a shock response that causes hyperventilation or 'gasping.' Think about jumping into a cold pool as a child. That gasping or 'shock' from the cold is the body's response when falling into icy water. The shock response can be lethal because the individual could inhale water and drown.

After the shock response, the body then progresses into more debilitating stages of cold water immersion. These final three stages include:

  • Incapacitation (the body is incapable of moving / swimming)

  • Hypothermia from immersion

  • Cold-water collapse

How Do You Assume the HELP Position to Reduce Heat Loss in Cold Water?

The HELP position is an acronym that means Heat Escape Lessening Posture. To keep heat from escaping the body too quickly when falling into icy water, tuck the knees to the chest and curl into the fetal position. Arms should hold the knees upright. This position will not prevent hypothermia, but it could save heat loss for a short period of time.

Cold Water Safety

Water doesn't have to be frozen to pose a danger for hypothermia. Water that is below 70 degrees Fahrenheit can lead to hypothermia. Even bodies of water during summer can fall to temperatures low enough to trigger a fatal response when the body is submerged for an extended period. Ultimately, the individual will lose consciousness, and drowning is likely to occur. 

Be mindful when swimming in any natural body of water; water temperature varies as the depth increases. Always wear a life jacket, never swim alone, and carry a cell phone. Obviously, a cell phone submerged in water will do little good, which is why boating and swimming with friends are the recommendations. If someone struggles in the water, a friend or family member can dial 911 and seek help. When an individual falls through ice, do not venture onto the ice; remember to grab a rope, a ladder, or even jumper cables to pull them out, and always call 911.

Also, remember that children can drown in mere inches of water. Never EVER leave a child unsupervised near a body of water.

FAQ: Ice and Cold Water Safety

How cold does water have to be to get hypothermia? 

Water below 70 degrees Fahrenheit poses a risk of hypothermia. During summer, water can be frigid. However, as long as the swimmer can safely navigate into and out of the water, cold water should not be a major concern. Falling through ice or into freezing water is an emergency and requires the assistance of first responders.

How long can you be in cold water safely?

The length of survival time in cold water depends on the temperature of the water. Shock sets in when the body is immersed in cold water, and this response can be fatal.

How do I make sure ice is safe?

Ice must be at least four inches thick to withstand the weight of an individual. A non-professional individual cannot determine the thickness by sight, as ice thickness must be prNearly every year in Missouri, a fall through an ice-glazed body of water leads to injury or death. In 2022, two individuals fell through ice-covered Creve Coeur Lake; the duo suffered no injuries (thanks to first responders). While walking across a seemingly solid body of water might seem like a fun shortcut or an ideal makeshift ice rink, that sheet of ice is likely deceiving. operly measured. For this reason, always assume the ice covering frozen bodies of water is fragile and unsafe.

How safe is white ice?

White ice is mixed with snow, which is why it looks white. This mix includes air, making the ice more fragile and unstable. White ice IS NOT SAFE.

Why is the rink ice white?

Rink ice is not white because it consists of white ice. Instead, the ice is painted white! Never assume that the white ice on ponds and lakes is the same as white ice on the rink. White ice on the water is fragile and dangerous, while rink ice is painted and ideal for skating.

About the Author

Wentzville Fire District is one of the largest fire districts in St. Charles County, covering 88 square miles. The fire district is committed to serving and protecting our community through the highest quality of fire protection, prevention, education, and community outreach.

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