The region containing a legendary white dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:
- Chilly fog lightly obscures the land within 6 miles of the dragon’s lair.
- Freezing precipitation falls within 6 miles of the dragon’s lair, sometimes forming blizzard conditions when the dragon is at rest.
- Icy walls block off areas in the dragon’s lair. Each wall is 6 inches thick, and a 10-foot section has AC 5, 15 hit points, vulnerability to fire damage, and immunity to acid, cold, necrotic, poison, and psychic damage.
If the dragon wishes to move through a wall, it can do so without slowing down. The portion of the wall the dragon moves through is destroyed, however.
If the dragon dies, the fog and precipitation fade within 1 day. The ice walls melt over the course of 1d10 days.