So I have one of Kylorin's sons that is able to use this ability... problem is I don't know how to use it :D
I stand in one of the (several) tiles under a storm but the ability button is still greyed out. What am I missing ?

PS: awesome job guys... this scenario is just perfect, as is the expansion as a whole. Kudos to everyone

You have to be in the center of the storm, which is hard to tell by eye-balling it. Look at the tile info, I think, and it should say blizzard.
Then heat will allow you to remove the blizzard if you are standing there.

thanks, I got it !