We are trying to make the most of the snow indoors and outdoors as it’s unlikely to have it for long.
Here’s an indoor idea with snow. Bring some snow in a plastic box and dilute some paints with water (or use food colouring). Painting works better on snow balls. Don’t forget to put a towel underneath or some sort of cover to protect your floors.
Unavoidably they will like to try and get inside the box. Make sure they do that before they put all the colours in :p.