Blast Zone

A blast zone is the resulting irradiated area created when a nuclear warhead makes impact, identified as a red circle on the map.

Background
A player character who has completed Mission: Countdown in any of the three nuclear silos (Alpha, Bravo, Charlie) may use a nuclear keycard to enter the weekly launch codes, allowing access to the targeting computer which fires the warhead and triggers Death from Above!.

Before the nuke is launched, a broadcast warning alerts the entire server of the nuclear strike and an air raid siren sounds. It will take three minutes for the bomb to drop. Player characters and most workshop objects inside the circle when the nuke drops will be destroyed instantly, while those inside of an interior location will be safe.

Player characters on the edge of the blast zones will not be killed. Once a player character has entered the zone, they will take severe radiation damage unless wearing power armor or a hazmat suit. Well-equipped player characters (Level 50+) are recommended for these sites.

These sites are excellent areas to level up and harvest raw flux, which is acquired by harvesting the following mutated flora in nuked zones:

Public events
If a nuke is launched at specific locations on the map, a public event with a high-level boss enemy will begin.

Protected zone
While where a nuke is launched is dependent on the choice of the player character, certain portions of Appalachia are in a "protected zone" and cannot be targeted. The protected zone includes many areas of Appalachia where low-level player characters are likely to have early quests. If any part of the blast radius would be within the protected zone, the nuke cannot be launched.

Nuclear Winter
In Nuclear Winter, player characters must obtain four launch codes and a nuke briefcase before gaining the ability to drop a nuke. By activating the briefcase, a targeting computer allows the player to drop a nuke anywhere they choose. Similar to Adventure mode, the blast radius will instantly kill any players inside at the time of impact and will leave a red radioactive circle for a duration. Unlike Adventure mode, the countdown timer is reduced to 20 seconds and the blast zone is comparatively smaller.

Behind the scenes

 * The orange weather seen from inside of a blast zone is a subtle reference to the song "Orange Colored Sky" by Nat King Cole.