Ice strike is magical, Meglobob
What I'm talking about would probably be as effective, or more so, cost a hell of a lot less, not require any magical training, gems, or resources that wouldn't be available on any significantly high mountaintop or cold enough environment, and carry with it a good possibility of blindness, poison damage, damage to feet, concussions, etc.
Oh I forgot-you could fill the ice with brightly colored dye, which would make the targets easier to track at height.
That's not even mentioning that Caelum has easy access to magical ice.