Would there be a case for keeping them separate? "Ice" could apply to ice on the ground surfaces, or even hail.
I think icing is the general one. Going by the dictionary icing is also a noun. But here's why I'm leaning toward icing:
The formation of ice on an aircraft, ship, or other vehicle, or in an engine.
This post is also asking about snow but we don't have a snow tag, moreover I think just the already existing tag cold-weather should be enough to cover ice and snow [and frost] for that post.
How ice forms is icing especially in the context for aviation.
* If there is any that I missed, let me know and I'll update the post.