Why You Really Shouldn't Eat Yellow Snow

Common and Rare Causes for Yellow Snow

'JOY' written in the snow.
Don't eat the yellow snow!. harpazo_hope / Getty Images

Yellow snow is the topic of many a winter joke. Since snow in it's purest form is white, yellow snow is said to be colored with yellow liquids, like animal urine. But while animal (and human) markings can indeed turn snow yellow, these aren't the only cause of yellow snow. Pollen and air pollution can also lead to large areas of snow cover that looks like lemonade. Here are the ways snow can acquire a golden hue.

Blanketed in Spring Pollen

One harmless reason for yellow-tinted snow is pollen. Common in spring snows when flowering trees are already in bloom, pollen can settle in the air and on snow-covered surfaces, marring the white color of snow. If you've ever witnessed your car covered in a thick coat of yellowish-green mid-April, then you know how thick a coating of pollen can be. It's the same with spring snows. If a large enough tree is overhead above a snow bank, the golden appearance of the snow can be spread over a large area. The pollen may be harmless unless you happen to be allergic to it.

Pollution or Sand

Snow can also fall from the sky with a yellow color. Yellow snow is real. You may think snow is white, but other colors of snow exist including black, red, blue, brown, and even orange snow. 

Yellow snow can be caused by air pollution as certain pollutants in the air can give snow a yellowish tinge.

Air pollutants will migrate towards the poles and become incorporated into the snow as a thin film. As sunlight hits the snow, a yellow hue can appear.

When snow contains particles of sand or other cloud seeds, it can be a source of yellow or golden snow. When this occurs, the color of the condensation nuclei can actually tint the ice crystals yellow even as it falls through the sky.

One example was in South Korea when snow fell in March of 2006 with a yellow tint. The cause of the yellow snow was an increased amount of sand in the snow from the deserts of Northern China. NASA's Aura satellite captured the event as weather officials warned the public of the hazards contained within the snow. Yellow dust storm warnings are popular in South Korea, but yellow snow is rarer.

Yellow snows often cause concern that they come from industrial waste. An intense yellow snow fell in areas of the Russian Urals region in March 2008. Residents worried that it came from industrial or construction sites and preliminary reports said it was high in manganese, nickel, iron, chrome, zinc, copper, lead, and cadmium. However, the analysis published in Doklady Earth Sciences showed that it was due to dust swept up from the steppes and semidesert of Kazakhstan, Volgograd, and Astrakhan.

Don't Eat the Yellow Snow

When you see yellow snow, it's best to avoid it. Regardless of what caused snow to turn yellow, it's always safest to find fresh fallen, white snow whether you'll be using it for snowballs, snow angels, or especially snow ice cream.