Snow is indeed an edible substance as it is made mostly of water. That being said, snow does contain other chemicals that it catches from the atmosphere as it falls to the ground, like carbon, or soot for example that can come from burning wood or coal. These chemicals in the snow are well below levels that would be harmful to humans though, so it is certainly edible, but best to eat when the snow is fresh.

If snow has been on the ground for a few days, it’s best to not eat this snow as it begins to accumulate bacteria from dirt and animals. In this case, if you must eat the snow, you need to melt the snow on the stove and boil it in order to get rid of bacteria.