I suppose that, for the sake of "power balance", the Elements of Destruction aren't normally present in Equestria. They would theoretically only manifest in the event that strife, conflict, and overall destruction passed a minimum "consistent threshold".
That is, Equestria would have to be on a steady approach towards becoming a true "crapsack world", with very little overall indication that things would ever resolve in a timely manner. At which point, the Elements of Destruction would begin to manifest.
Here's how it could work:
- Storm would manifest first, completely circumventing any attempt to manually control the weather like the Wonderbolts do, and inducing massive superstorms across the land.
- Earth would manifest second, tearing and fracturing the very land with massive earthquakes, extremely violent volcanic eruptions, and devastating tsunamis along coastal areas.
- Fire would be the third to manifest, increasing the frequency and intensity of possible firestorms by inducing more frequent lightning strikes from the superstorms, as well as increasing the magma and lava temperatures of the already destructive induced volcanism.
- Cataclysm would be the fourth and last Element of Destruction to manifest in Equestria during a "crapsack event". Wielding devastating control of all three previous Elements, its arrival signals the start of a final disaster of the same name; a Cataclysm. Through the all-consuming destruction that it and the first three Elements unleash upon Equestria, most sentient life is either completely wiped out, reduced to unrecoverable numbers, or culled sufficiently enough that the "crapsack outcome" can never occur; desperate survival trumps petty hostilities, after all.
I just realized that I unintentionally played the "Four Is Death" TV Trope frighteningly straight with my "concept" here; I have four Elements of Destruction here, and the fourth is the most powerful. The end result of their manifestation is usually death, especially so with the fourth as Cataclysm.