Planestorm
A planestorm (riftstorm, shattersky, worldsquall) is an instance of unruly arcane weather characterized by one or more transient, unstable rifts from one world or plane of existence into another. These rifts (skybursts, planeways, veilbreaks) may be as small as a fist or as large as a village, are often shaped like a ragged tear or canyon, and may last for mere seconds or up to months at a time. A planestorm may have multiple rifts to the same or different locations; some rifts may overlap the same material-plane location, creating a threeway intersection between realms. For reasons still unknown, planestorms do not form lower than several hundred feet from the ground, and some may be thousands of feet up.
A planestorm is usually, but not always, accompanied by a mundane storm of some variety; high winds and some precipitation are typical, but which planes are currently accessible via rifts have considerable influence on how the mundane storm manifests. If a passage to the elemental plane of fire is active, for example, a heatwave may strike with high likelihood of boiling rain; if a rift to the elemental plane of air is active, dozens of tornadoes and lightning strikes may descend. The size of the rift determines how much of an effect the linked plane can have on the local mundane weather. Rifts that are exceptionally high in the sky may have turbulent effects that never reach the ground and those living there.
While it is theoretically possible for a planestorm to occur anywhere in the world, the only documented instance of such a realm-spanning tempest in Aerune is in the skies over the island of Molthuth. Centuries of near-constant rifts over Molthuth has resulted in a new strain of tieflings, plane-touched tieflings, who eventually formed a defensive organization of planewardens to limit the interplanar travel through the storm's unstable ingresses. Planewardens prevent Aerunians from approaching the storm and rebuff any incursions from extraplanar entities, as well as protect their ground-based settlements from recurring natural disaster. Skyguards, an elite branch of planewardens, risk life and limb to venture closest to the open rifts, into the heart of the tempest, to mitigate the worst of the elemental effects and to handle any would-be planar travelers.
