How would one apply snow to an entire scene?

I have a scene i worked up a while ago and for festive shits and giggles id like to winter it up a little and add a layer of snow over everything.
Any ideas how i could accomplish this quickly? It has a hell of alot of scattered trees but its a low poly stylised scene so it isnt heavy at all.

Thanks
Jack

I used snowflow plugin a long time ago, perhaps see if that can do what you require…

I did have a look at that and it seems you need to simulate and have a separate pflow for every scene object. its a pretty big scene unfortunately. Id love it if i could somehow use world space normals to mass apply a material ontop of a scene but thats probably complicated as hell!

SnowGun maybe ? http://hocuspocus-studio.fr/tools/product/snow-gun/