[X] Plan Strike down from the Heavens:
-[X] The sky is not your domain— it rules the storm and flies faster than you do.
--[X] Prepare a plasma sphere, or more if you are confident in your ability to move with them, or multiple thermal spears if you are not and use halt on it before attacking with them all.
--[X] Use the water against it- Form ice around it's body to drag it down. Keep at it until it has neutralized your ability to do this or you have dragged it down to earth through sheer weight.
--[X] Use the ice thermal Spear to hit it with freeze.
--[X] Keep up fire around its head to blind it
--[X] Use the water from the storm to make blocks of ice in the direction it is flying so that it has to dodge or stop. If it tries to break through the ice, use halt on the ice.
--[X] stay a good distance lower than it, you'd rather not be hit with lightning from the storm if you can help it, and it going closer to the earth only helps you.
--[X] If it starts to build up speed despite all these measures use halt to break that momentum.
--[X] Use ice to try to limit its ability to fly away, you must not let it flee.
--[X] Attack with thermal Spears or Plasma Spheres whenever you get a good oppurtunity. Try to take it down fast.
--[X] Try not to damage the mountain in any way, you don't want to deal with whatever is making it so hot.
---[X] If all else fails call in the air strike, but inform them to not shoot in such a way that a miss could hit the mountain.