Snow Cloak (Japanese: ゆきがくれHidden in the Snow) is an Ability introduced in Generation IV.
Effect
In battle
During hail or snow, the accuracy of any move used against a Pokémon with this Ability is modified by a factor of 4/5 (in Generation IV) or 3277/4096 (in Generation V onward). A Pokémon with this Ability will take no damage from hail if it otherwise would.
Outside of battle
If a Pokémon with Snow Cloak is in the first place in the party (even if fainted) in an area with hail, the chance of encountering a wild Pokémon is decreased by 50%.
While it is hailing, Froslass can repeatedly appear and disappear throughout the battlefield. She can also become intangible, allowing her to avoid attacks.
While it is hailing, a white mist forms around Alolan Vulpix's body, allowing it to hide within it and make it more difficult for its opponent to aim at it.