Event · M31–M32
Doom of Valhalla / comet impact
The Doom of Valhalla was the impact of an iron comet that displaced the planet Valhalla from its orbit and froze its oceans. The event changed Valhalla from a green colony into the frozen world it remains today. Before the impact, Valhalla was a green colony. The comet moved the planet out of its orbit, and the loss of that orbit froze the oceans. The survivors responded by excavating cities into the ice so that they could endure the new conditions. The ice-buried cities that resulted are among the features for which Valhalla is now known. Later, in the War of Survival, the population fought the Orks, and that conflict left them with a lasting hostility towards the species. Valhalla supplies Ice Warrior regiments, whose members treat the cold as an advantage on their home ground. Since the Rift, the planet has lain within Imperium Nihilus, the region of the Imperium cut off by that disturbance.
See where Doom of Valhalla / comet impact occurred on the galactic map in the 41st Millennium.