So...I have a very dwarven fortress, lots of tiny rooms, lots of copper, forges and a magma pipe. And with this lovely magma pipe, I decide to channel it to the edge of a map to the edge of my adamantine extraction, usinga channel to drop it to my storage bay. Sounds all gravy, my nice big magma tub is filled with magma to trigger my doom shoot for tentacle demons.
Well, my pipe keeps pumping out magma out onto the open hillside after my 4z level 30*2 magma tub fills up. Dig some channels, divert the flow down the hillside.
The dwarven caravan comes by. The diplomat gets immolated and stomps away unhappy. The wagons are smarter and go around. They then ride above the warm ground, and after about 60 tiles....BURST INTO FLAMES! All six of them,
I have flaming wagons riding toward my depot. Their horses are screaming,the wheels are flaming and their food is burning as the caravan wagon merchants keep riding. My firefighting dwarves look on. Since there's no water on the map, they just shrug and take the steel armor on board, Although, one tries throwing snow onto the wagons with no effect.
Now admittedly i'd channeled the magma from the center of my map to the nearest map edge which parallels the path the caravans took. And, I'd like to think it's really NOT because the heat from the warm ground burst the wagons into flame.
tl:dr - Did the last caravan burst into flames because the wagons were riding too close to my nice new magma lake I've built?
Did the caravans burst into flames because of excessively warm ground?