Floods: 32x Water Brick Spam?
Storms: Lighting works, but changing the sky like that gradually...
Metor shower: AoT has those, but...forgot settings you need for it.
Volcanos: Running Lava = No.
Sandstorms: Low sand-colored Fog setting with slowed down player datablock and slow damage.
Snowstorms: Same.
Overfreeze: Tried to find definition, doesn't exist. Can only assume you mean everyone turns white and can't move :P