snophieDepends where you are also, in Australia i feel like any new snow classifies as a pow day. But somewhere else like Japan, I'd say enough to cover your tracks for the next run
This is true. In Japan, 15cm of fresh (unless it fell in the last 15 minutes on top of 60cm of newish snow) may as well not be there, it's so light and soft that you can't float on it even with the fattest planks.
To me anything from 1-20cm is more like "freshies"
20-40cm is "pow"
40cm+ = "deep pow"
But it depends quite a lot on the density of the snow and what it fell on.