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.
One of its uses is aviation specific. So I checked the ice posts to see if they can't have the icing tag. I found only two cases* that might be debatable.
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.
Based on that I suggest turning ice into a tag synonym of icing, so anyone who would type 'ice' in the future, wouldn't create the tag again.
* If there is any that I missed, let me know and I'll update the post.