The Ash Cloud is a block added by Natura. Ash Clouds spawn naturally in the Nether dimension. Entities will not be able to fall through the bottom of the block or the bottom block of an Ash Cloud column. Entities that have fallen into an Ash Cloud will not take any fall damage. Ash Clouds break fastest with swords, but can be harvested with anything. Combining 9 Ash Clouds in a Crafting Table will create a single Charcoal.