It would be best if you were wary of eating or processing snow that is not entirely white. Snow that is discolored is an indication that it is visibly contaminated and not safe to consume.
Varying environmental conditions, including air pollution, animal droppings, unseen fungi, roadway chemicals, algae, pollen, soot, and dust, are the leading causes of snow to be discolored.
In fact, in a recent study by Scientific American, “thawing permafrost is releasing microorganisms, with consequences that are still largely unknown.”
For more information on their findings, click here.