It might seem a little obvious to avoid putting yellow or discoloured snow in your mouth… but what about the fresh looking white stuff?
Snow is crystallised water, meaning it's purer than most types of precipitation. It's essentially frozen distilled water, crystallised around a tiny particle, so it could potentially be purer than the water coming out of your tap.
It all comes down to location and how “fresh” the snow is - when considering consumption.
Stephanie Smith, consumer food safety specialist and assistant professor at Washington State University, commented that location is everything when it comes to snow-eating. “If the snow is falling from the sky, and you open your mouth to catch a few flakes, it is very unlikely that it will cause any illness.”
Though she did continue on to explain: “as a food safety specialist, I do not recommend that people eat snow that has fallen on the ground or come into contact with another surface.”
Fresh snow that’s fallen, say, on top of a mountain is more or less safe to eat (or to melt and drink; mountaineers do it all the time) in small quantities. If you are planning on drinking melted snow, keep in mind that because it’s condensed water vapour it’s technically distilled water, which is toxic without the addition of a small amount of salt.
You can help ensure extra purity by running the melted snow through a coffee filter. If you have electricity, you can boil the melted snow.
Make sure to use the freshest snow you can find. Wind deposits a fine layer of dirt and pollutants onto the top layer of snow within a day or so - meaning week old snow is not a great snack.
Snow does seem to be a bit of winter delicacy in North America as numerous recipes suggest. With a quick Google search you’ll find plenty of “snow ice-cream” recipes online. Most of these have four simple ingredients - evaporated milk (or fresh cream in some cases), sugar, vanilla essence, and “fresh snow”.
It is generally okay to eat fresh snow, use it for drinking or to make ice-cream, but there are some important exceptions.
When not to ingest snow
If you ever find yourself stranded high up in the mountains under extreme cold conditions - this is not the time to turn to snow for hydration purposes.
Consuming snow under these conditions can actually lead to further dehydration due to the process your body has to go through to heat and melt the snow once you eat it. It can also lead to hypothermia. If the snow has been on the ground for a significant period of time it could contain bacteria and other organisms that can make you ill. If you are looking for water and only snow is available - always try to melt it before consuming. The deeper and more compact the snow is, the more water will be produced on melting.
If it’s not white and fresh - stay well away
If the snow is “white as a lily”, it can be relatively safely consumed, if not - you could make yourself ill by consuming varying snow shades.
If you come across yellow snow - it’s an absolute no
Yellow or discoloured looking snow is a huge warning sign that it is contaminated. It could be urine, dirt, algae or other bacteria - which are all harmful if ingested.
Regardless of its colour, it is recommended to avoid eating snow near roads - especially in urban settings. Exhaust fumes may no longer contain lead particles - but roadside snow can still absorb other toxic chemicals ejected by vehicles.
A 2015 study from the McGill University, Canada, investigated the impact of vehicle fumes on snow in an experiment. They pumped chemicals found in a vehicle exhaust into a sealed chamber of freshly collected snow. After one hour, the snow had absorbed these hazardous chemicals, including BTEX compounds (benzene, toluene, ethylbenzene, and xylene) found in petroleum products. Low levels of exposure to BTEX can cause headaches, dizziness, and confusion, but long-term exposure and directly ingesting high levels of BTEX could lead to more severe complications including liver and kidney issues or potentially cancer.