# White Dragon ## Regional effects _Source: Monster Manual (2024)_ The region containing an adult or ancient white dragon's lair is affected by its presence, creating the following effects: - **Frigid Cold.** The area within 1 mile of the lair is an area of [extreme cold](3-Mechanics/CLI/traps-hazards/extreme-cold-xdmg.md). Any water in that area is [frigid water](3-Mechanics/CLI/traps-hazards/frigid-water-xdmg.md). See the "Dungeon Master's Guide" for rules on extreme cold and frigid water. - **Glacial Gloom.** The area within 1 mile of the lair is [Lightly Obscured](3-Mechanics/CLI/rules/variant-rules/lightly-obscured-xphb.md) by chilly fog. Whenever a creature other than the dragon or one of its allies finishes a [Long Rest](3-Mechanics/CLI/rules/variant-rules/long-rest-xphb.md) in that area, that creature must succeed on a DC 15 Constitution saving throw or have its [Speed](3-Mechanics/CLI/rules/variant-rules/speed-xphb.md) reduced by 10 feet for 1 hour. If the dragon dies or moves its lair elsewhere, these effects end immediately.