whale n. a large man-made snow mound. Editorial Note: Usually resulting from a commercial snow-grooming machinery typical of a ski resort. Etymological Note: So-called because of their large, round shape and perhaps influenced by “whale” meaning “a large or significant example of a particular thing,” as in “I have a whale of a headache.” (source: Double-Tongued Dictionary)
Further reading
Sure, there’s winter, spring, summer, and fall. But the seasons in between have even more poetic names. In Alaska, greenup describes a sudden, dramatic burst of green after a long, dark winter. And there are many, many terms for a cold snap...
A North Carolina listener is fond of the German loanword Weltschmerz, literally “world pain,” a compound word made up of Welt, cognate with English world and Schmerz, cognate with smart as in That smarts! Coined by a 19th-century German author who...
I would imagine that the snow color helping the mound look like a great white whale (Moby Dick) has something to do with it too.