A Warp Storm is a place where the Warp bleeds out into realspace. They are caused by calamitous events or by increased daemonic activity in the Warp, and are incredibly dangerous to travel through for Warp-powered interstellar vessels. Warp Storms can be small rifts barely larger than a starship that last for a few days, or they can be near-permanent overlaps spanning multiple sectors that last for thousands of years or longer, but all of them are effectively impassible to ships not allied with the powers of Chaos.