at least one legendary pokemon is causing the storm. there may be more than one, causing it to be such an enduring shitshow - lugia and its 40-day typhoons, zapdos and its power over whirlpools and currents, kyogre and the endless rain have all been brought up icly

there's currently no way to stop it while remaining on toran, but there may be clues to stopping it in future locations.

the best clue to figuring out what parties are in play here is the volcanic lava sand and rising water level in the NW, suggesting the new emergence of a volcano, but this would not exactly be the source of the storm, so i don't know which direction is best for that.