Radstorm

Radstorms, also called radiation storms, are weather phenomena that occur throughout and around the Commonwealth, Appalachia, and The Island.

Background
Radstorms from 2102 and onwards often result in green overcast skies, audible winds, and lightning. An approaching radstorm will give off a clap of its distinctive thunder to signal its arrival. Over the course of the storm, lightning periodically flashes and causes a brief spike of radiation in the area, inflicting 5 rads per lightning flash. Sheltering within the interiors of buildings during radstorms will provide protection and reduce the amount of accumulated radiation.

Radstorms directly after the Great War were often extremely violent and could result in storms capable of lifting people into the sky. These original storms would be the cause of death and ghoulification for many people who were often unprepared for such weather.

Randall Clark also describes a possible radstorm as far back as January 2078. In his description, the storm lasted two days and once it was over radiation levels had subsided from previous highs of 500. Looking outside his cave home, he found glowing green snow covering the ground.

Locations
In the Commonwealth, radstorms are far more common than any other area. This is thanks to the close vicinity of the Glowing Sea. Often atmospheric pressure systems of the area sweep that radioactive material of the Glowing Sea and throw it into in the metro area of Boston.

In Appalachia, radstorms can usually be seen approaching from the distance by their appearance, which is a green version of the clouds created from the blast zone of a nuke. Once they have passed over the player characters, they will absorb radiation from the storm unless wearing power armor or a hazmat suit to reduce the radiation absorption until the storm has subsided or moved on before dissipating. Rad-X can be used as a temporary means to reduce the radiation damage while the storm is active.

Appearances
Radstorms appear in Fallout 4, its add-ons Far Harbor and Nuka-World, and Fallout 76.