I don't use Shadow World, or Essence Storms, but my party is in a part of the world where the storms turn to firestorms. One thing that I have tried to do with these and other "natural events" is to incorporate smell, sound, or taste into the descriptions. We rely a lot on visual, but just a mention of some particular smell or taste, especially, can make a big difference in how completely players imagine these things. You can do it with creatures too, the most obvious being zombies smelling of rotting meat.
Maybe essence storms are preceded by a faint smell of citrus on the wind. Or fresh-cut grass. But not ozone, that would be a regular storm.