I cast my lot with JS here, I think of the plastic slopes at Liberty University and in the UK as "artificial." BUT the use of the phrase "artificial snow" is quite common, PBS refers to it, Olympic athletes, etc. so, as language is an ever-evolving thing, I accept it.
My bigger beef is with the word "snow" -- my understanding (could be wrong) is that on a microscopic scale, man-made (or artificial) "snow" is actually a bunch of ice crystals rather than snowflakes. Perhaps technology has advanced recently and I'm unaware of it?
If you made him out of any man made (or artificial) snow, he'd be Frosty the Iceman instead of Frosty the Snowman.
Speaking of names/words, Frosty was almost named Oatmeal, but it was overwhelmingly rejected by voice vote. (a little trivia there)
Anyway, Frosty aside, McGill University has a piece on "artificial snow" (their words) in which they also decry calling it "snow."
Here's a link, and it's written by a doctor.