Yes, it's true! There is such a thing as purple snow. I learned that by researching snow with my students. In fact, if you Google purple snow, you will see that a portion of southern Russia was blanketed with purple snow in March of 2010. One of the interesting facts that my students and I learned is that snow can be a variety of colors, depending on the dust in the air. The purple snow in Russia had dust from Africa!
Maybe the snow wasn't this deep, dark purple, but purple snow does exist!