What happens if I eat a lot of snow?

December 12, 2025 •

4 min read

While a small taste of fresh, clean snow is often harmless, consuming a large quantity of snow can lead to serious health complications. Your body expends significant energy to melt the frozen water, potentially causing a dangerous drop in core temperature and, surprisingly, even dehydration.

Quick Summary

Consuming a large volume of snow can introduce contaminants like pollution and bacteria into your body. Additionally, your body uses a lot of energy to melt the snow, which can cause dehydration and lower your core temperature, increasing the risk of hypothermia.

Key Points

Contaminant Ingestion: Eating large amounts of snow increases the risk of ingesting atmospheric pollutants, chemicals, and bacteria picked up as it falls or sits on the ground.
Risk of Dehydration: The body expends more energy and fluids to melt and process large quantities of frozen snow than it gains, which can cause dehydration.
Hypothermia Threat: Consuming cold snow can cause a dangerous drop in core body temperature, heightening the risk of hypothermia, especially in already cold conditions.
The Safest Approach: If necessary, melt and boil snow before consumption to purify it and prevent the body from using precious energy to warm it.
Urban vs. Rural Snow: Snow is generally more contaminated in urban and industrial areas due to higher levels of airborne pollutants, while even remote snow can contain microplastics and other contaminants.
Avoid Discolored Snow: Never consume discolored snow (yellow, pink, brown) as it likely contains animal waste, algae, or other harmful substances.
Melting is More Efficient: Melting snow over a fire or heat source is far more energy-efficient and safer than eating it directly, especially in a survival situation.

The Hidden Dangers of Eating Large Quantities of Snow

Eating snow seems innocent, a rite of passage for many children. However, beneath that pristine white blanket lies several potential health risks, especially if consumed in large amounts. The seemingly pure frozen water is not as clean as it appears, and the physical act of eating it can have counterintuitive effects on your body's temperature and hydration levels. Understanding these dangers is crucial for anyone, especially in a survival situation, who might consider snow a viable source of hydration.

Contaminants: The Invisible Threat

As snow falls through the atmosphere, it acts as a natural air filter, picking up various pollutants. These contaminants can include everything from car emissions and industrial pollutants to pesticides, microplastics, and heavy metals. A study by US and French researchers even found that a large portion of particles in snowflakes consists of bacteria and other microorganisms. While most of these pathogens are inactive in the freezing cold, they can become active once inside your body. The longer the snow sits on the ground, the more contaminants it collects from the soil, debris, and animal waste.

Atmospheric Pollutants: Snowfall can collect particles like black carbon, sulfur dioxide, and nitrogen oxides from car exhaust and factory emissions.
Ground-Level Contaminants: Snow that has been plowed, walked on, or is near roadways can contain salt, chemicals, and other debris.
Biological Agents: Animal droppings and other organic waste can introduce harmful bacteria like E. coli into the snow.

The Dehydration Paradox

This is perhaps the most surprising risk of consuming large amounts of snow. You might think you are hydrating yourself, but the opposite is true. Your body has to expend significant energy to melt the cold snow and bring it up to your core body temperature. This process, called thermogenesis, consumes more fluids and calories than the small amount of water you receive from the melted snow. In a survival situation, where calorie conservation is critical, this energy drain is particularly dangerous, leading to further dehydration. The effect is similar to drinking seawater; your body has to work overtime to process it, leaving you worse off than when you started.

Hypothermia Risk

Just as your body has to work hard to melt the snow, it also has to work to maintain a stable core temperature. Eating large quantities of ice-cold snow, especially in an already frigid environment, can cause a sudden and significant drop in your internal temperature. The digestive tract becomes chilled, triggering a vasoconstriction reflex that further reduces the body's ability to retain heat. For children and thinner individuals who have less thermal insulation, this is an especially serious risk. In a severe hypothermic state, your body's essential systems begin to shut down, leading to potentially fatal consequences.

Comparison: Eating Snow vs. Melting Snow


Feature	Eating Raw Snow	Melting and Boiling Snow
Energy Expenditure	High. Your body must use precious internal energy to melt the snow.	Low. External heat source is used, conserving body heat.
Contamination Risk	High. Ingests atmospheric pollutants, bacteria, and ground debris directly.	Low. Melting and boiling purifies the water by killing pathogens.
Hydration Efficiency	Inefficient. Can lead to a net loss of fluids and cause dehydration.	Efficient. Provides safe, easily digestible liquid for rehydration.
Core Temperature	Decreases. Significant cold intake can lower your core temperature.	Stable. Warm or lukewarm water helps maintain body temperature.
Gastrointestinal Issues	High. Potential for stomach cramps, vomiting, and diarrhea from cold or contaminated snow.	Low. Boiled water is less irritating to the digestive system and is sterile.

The Safest Way to Consume Snow

In a dire survival scenario where snow is the only available water source, the safest method is to melt and boil it before consumption. Use a clean container and a heat source, if possible. Place a small amount of snow in the container first and allow it to melt before adding more. This prevents scorching and saves fuel. The boiling process will kill any harmful bacteria and viruses present. Avoid melting snow on a flat, super-hot surface to prevent contamination from melted material. Remember, it takes a large volume of snow to produce a small amount of water, so manage expectations and resources accordingly.

Conclusion

While the romantic idea of eating pure, fresh snow persists, the reality is far from pristine. Eating large quantities of snow can lead to a cascade of health issues, including ingesting dangerous contaminants, exacerbating dehydration, and increasing the risk of hypothermia. The next time you're faced with a snowy landscape, remember that a handful of snow is not worth the risk. Instead, focus on finding a safe way to melt and purify it if your situation demands it. When in doubt, it's always safer to skip the snow altogether and seek a reliable, clean water source. https://www.prevention.com/health/a34618470/is-it-safe-to-eat-snow/

Frequently Asked Questions

Yes, you can get sick from eating snow. Snow can contain contaminants such as bacteria, viruses, chemicals, and heavy metals. Eating large amounts of contaminated snow can lead to gastrointestinal issues like stomach cramps, vomiting, and diarrhea.

Yes, it can. Your body uses more energy and fluids to melt the cold snow than the small amount of water it provides. This process can lead to a net loss of hydration, making you more dehydrated in the long run.

Consuming large quantities of ice-cold snow, particularly in a cold environment, can rapidly lower your core body temperature. This increases the risk of hypothermia, which is especially dangerous in survival scenarios.

Freshly fallen, clean, white snow from a relatively pollution-free area is the safest option. However, even this can pick up contaminants as it falls through the atmosphere. It is generally safer to eat snow that has been falling for a few hours, as it can clear some initial pollutants from the air.

Snow that has been on the ground for an extended period has had more time to accumulate dirt, debris, animal waste, and other contaminants. Snow that is discolored, shoveled, or near roads should always be avoided.

Yes. Melting and boiling snow before drinking it is the safest method. This process purifies the water by killing pathogens and ensures your body doesn't expend unnecessary energy to melt the snow internally, which is more efficient for hydration.

Snow is largely composed of air, so it requires a significant volume of snow to yield a small amount of liquid water. Depending on the density of the snow, it can take an entire pot or more to produce one cup of water, as some experienced during a power outage.