Natural Disasters-They're already overpowered in design but if it is then it would be. I doubt this is it since it'll be a storm type catastrophe with most of the disasters. All of the Sky flames
all connect with each other, they are all part of the theme of what takes appears in the sky. Most of the suggestions on the Earth flames are just random elements comaparing to Sky flames. The
earth flames need to connect with each other and as well with the sky flames.
It's supposed to connect with all the other Earth Flames, just because it holds the Earth together doesn't mean it has direct connection. right now I'm in a bad position but I'll find the pages which show how the Sky flames connect. Also its almost a given the Enma's flame is "Earth" as Tsuna's Flame is "Sky". It's obvious that it's the earth counterpart to sun, first of all. Apart from both the sun and plants having sort of an "activation", i suppose we can assume there are similarities like this between the other sky/earth flames.
MOST people say that their flames match up or are somehow related in some aspect is because Ryohei and Kouyou are are almost equals and fit each other. when they first meet they both act the same and are drawn to each other. I would say that the others flames are things like Ocean, Vulcan, Desert, Mountain, Swamp, Tundra...Maybe Vulcan can match with Storm, in Degeneration. Mountain with Lightning, in Solidification. Ocean with Rain, in Tranquility. Swamp with Mist, in Construction.