Magma mist will be generated in all tiles of magma that were in the path of the cave-in.Dwarves will receive an unhappy thought from choking on dust clouds (which won't matter if they're dead). Any creature caught by the dust from the collapse is knocked unconscious and can be thrown a few tiles even up z-levels, which may cause them to fall off, say, a narrow bridge fifty z-levels above the ground, or can mash them into a fine paste against the wall. The fall victim has a chance of being unable to walk away, somewhat proportional to the distance fallen but not set in stone.

Anything standing on the area that caves in falls and may get away with being stunned.Buildings above the cave-in will deconstruct if they are no longer supported.Dropping rock layers on top of a cavern-soil floor will remove the soil irrigation will be required to resume tree farming.Any mined minerals or stone in the area directly under the cave-in will be forced out from under the cave-in (or even up a few z-levels too, if the cave-in falls a long distance).This principle can be used to construct magma pistons. Any fluid displaced by falling natural walls is not destroyed, but transported to directly on top of the fallen walls.Supported natural terrain will remain intact during the cave-in (terrain unsupported from below will collapse).Only walls, supports, up and up/down stairs, and fortifications (both mined and constructed) remain intact. All buildings and most constructions under the falling area are destroyed, as are natural ramps and unsupported floors.Natural floors and constructed walls and floors have a chance of destroying items. Any item caught under falling natural walls is destroyed completely.Most plants under a cave-in are obliterated, but not multi-tile trees.To clarify, it will kill all non-ghost creatures between the tile below the initial tile caving in to its final resting point. Any creature caught directly underneath (on the same tile underneath) a cave-in is killed, the only exception being Ghosts.Aquifer tiles will continue producing water, and other tile properties will remain the same in the fallen terrain.Falling soil will change into the soil type at the layer it falls to, or the lowest type on the map if it falls into the stone layers.your gem pile was directly below and you had a magma tube three Z levels afterwards. Therefore, it is not a good idea to punch a skylight into your meeting area if you forgot that e.g. Anything falling into a fluid sinks to the bottom.Falling grass of all types (including cave moss and floor fungus) gets turned into undifferentiated green 'Grass'. Trees, shrubs and saplings that fall are obliterated.Falling natural floors, stairs and ramps will be destroyed, leaving behind a natural floor of the highest such terrain natural stone walls pile up and constructions deconstruct, leaving behind their building materials.Falling tiles do not stay connected in one mass each falling column will fall as far as it can as described above.Any unsupported terrain crashes down through multiple floors and ramps, and stops only upon reaching a wall, up or up/down stair, a fortification, a multi-tile tree, or a support.

No dwarf can enter the invisible floor, but it will hold an area attached to the floor tiles in four directions alongside it or the constructed/natural wall above it. Note that supports and fortifications, but not statues, create an invisible floor on the level above them.

Ramps will not provide support to the tile above them, but will act as a connection for the adjacent tiles on the same level. Diagonal connections and bridges do not provide support. Up stairs will provide support for the z-level above even if there is no downstairs above, acting as an invisible floor. Any construction, even stairs (natural or constructed), and supports (naturally) provide support/connections. The game checks for connections along the X, Y, and Z axes (that's left/right, up/down, and above/below).

4.1 Caving-in the toplevel/terrain from insideĪny disconnected construction or section of rock or soil will cave in.

Dwarf fortress cavern generation cave