Here's my variant on the same toy idea, using a CA, generated trees, and a few other tricks.

https://vps.kimbruning.nl/snow/2025/snow_singlecore_scalable...

Every year during snow season I try to make it faster/more flakes. After this year though in chrome, I think it'd be whiteout conditions ;-) (it'll auto-scale to try to match your system performance. Best effects in a clean browser with not too much else running/open at the same time)