You wouldn’t think twice about catching a snowflake on your tongue, but using snow to make snow ice cream or melting it for drinking water might get you wondering whether it’s safe or not. It is generally safe to eat snow or use it for drinking or for making ice cream, but there are some important exceptions. If the snow is lily-white, you can safely ingest it. But if the snow is colored in any way, you’ll need to stop, examine its color, and understand what it means. Also, it’s important to be aware of where you are collecting the snow. Read on to see when it’s safe to eat snow—and when it can pose a health risk.
Crystallized Water
Snow is crystallized water, meaning it’s purer than most types of precipitation. If you think about how snow forms in the atmosphere, it’s essentially frozen distilled water, crystallized around a tiny particle, so it might even be purer than the stuff coming out of your faucet. Campers and mountaineers all over the world use snow as their primary water source without incident. Even if you live in a city, you can eat clean snow.
Snow does fall through the atmosphere before hitting the ground so that it can pick up dust particles and other impurities in the air. If the snow has been falling for a while, most of these particles have already washed out. The biggest consideration for snow safety is where and how you collect the snow.
Safe Snow Collection
You don’t want snow that is touching the soil or street, so either scoop up clean snow above this layer or use a clean pan or bowl to collect fresh falling snow. If you intend to melt the snow for drinking water, you can ensure extra purity by running it through a coffee filter. If you have electricity, you can boil the snowmelt. Be sure to use the freshest snow you can find, since the wind deposits a fine layer of dirt and pollutants onto the top layer of snow within a day or so.
When You Shouldn’t Eat Snow
You probably already know to avoid yellow snow. This color is a big warning sign that the snow is contaminated, often with urine. Similarly, don’t eat other colored snow. Red or green colors can indicate the presence of algae, which may or may not be good for you. Don’t take the chance.
Other colors to avoid include black, brown, gray, and any snow containing obvious particles of grit or grime. The snow that falls around smokestacks, active volcanoes, and radiation accidents (think Chernobyl and Fukushima) should not be ingested.
The most common warnings about eating snow have to do with eating snow near roads. Exhaust fumes used to contain lead residues, which would get into the snow. Toxic lead isn’t a modern-day concern, but it’s still best to collect snow away from busy streets.
By Anne Marie Helmenstine, Ph.D.