Cloud



The Cloud is a massive, blood-red blanket of toxic smog, spewed over the dead city of the Sierra Madre by the air conditioning and climate control systems inside the Sierra Madre Casino.

Background
The Cloud is not a natural occurrence; it is an artificially created toxin. It was deployed in the Sierra Madre as part of a greater experiment, using the casino and the villa as testing grounds - with Sinclair fully unaware of this. The Hazmat suits worn by the ghost people were a follow up experiment to the Cloud, something many researchers in Big MT found disturbing. It is also pointed out in terminals at the Big MT research facilities that Sinclair was aware of the experimental state of the suits, but not of the Cloud.

The toxins were seemingly meant to force the usage of the newly created Auto-Docs. During the construction of the villa, construction crews discovered the gas backed up in the Sierra Madre's ventilation system, and attempted to inspect it. Even trace amounts of the gas proved to be harmful. Hazmat suits that were also developed in the Big Empty were ordered by the workers with the hopes that it would protect them. Unfortunately this wasn't the case; the workers were still exposed to the Cloud and the fastenings of the suits were corroded, trapping the exposed workers inside to the point where they had to be cut free with a cosmic knife. The exposed workers were sent to the medical district, and concerns were raised about the gas building up beneath the streets.

By the time the Courier arrived, two hundred years after the War, a number of the fans in the main ventilation system had gone offline, and the Cloud had completely engulfed the casino and villa, somehow preserving it despite the decades of disuse. Elijah sees the potential in this, and wants to use the Cloud in his new world, using it to preserve and cleanse Old World technology. He also plans to use it as offensive technology, unleashing it upon the Mojave, cutting it off from the rest of the world. He could then use modified REPCONN rockets to wipe out the New California Republic (NCR) at Hoover Dam, and finally let traces of it drift west to NCR territory, killing outlying communities there. He would then presumably reset the fans of the ventilation system to remove most or all of the Cloud around the Sierra Madre.

Characteristics
The Cloud slowly depletes the health of visitors to the Sierra Madre (during Hardcore mode), and concentrated pockets of it will deplete health far more quickly. Only the ghost people walk the Cloud, in their ancient hazmat suits fused to their bodies. Though the exact composition of the Cloud isn't mentioned, it's implied to consist of heavy metals: Elijah mentions that it contains copper and sulphur, and Dog/God will often remark on the cloud as tasting like copper, or "old world gold". The rebreather or any power armor will offer no protection from the Cloud.

During the quest Mixed Signals, the player can disperse part of the Cloud in the streets of Puesta del Sol by reactivating the ventilation fans (Christine will remind the player to do this). After the conclusion of Dead Money, when the player finds themselves in the central courtyard again, the Cloud in Salida del Sol South can also be cleared. At the right of the entrance to the Switching Station in Salida del Sol South, where Dog/God is stationed to discharge the fireworks for the Gala Event, there is a monitor used if necessary to lock Dog/God in the Switching Station. If this monitor is activated after the conclusion of Dead Money, it will show three sub-menus: Substation Status, Ventilation System Status, and Reset Ventilation System. Clicking on Ventilation System Status will bring up a display that indicates that two of the five main fans for Salida del Sol South, Fan 2 and Fan 5, are offline and need to be reset. This can be done via the Reset Ventilation System link on the main screen, and then all five fans are shown as back on line, and the Cloud in the streets of Salida del Sol South disperses (though it remains in pockets in some rooms, and the area outside the neighborhood is unaffected).

Appearances
The Cloud appears in the Fallout: New Vegas add-on Dead Money and is mentioned in a terminal in Old World Blues.

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