Random events

An airship comes down over a square, a bombing run flattens a block, a train derails along its track. They are a chance rather than a fixture: two battles on the same map can play out with and without one, which is why the game says an event might occur here. The area is marked before it happens, with smoke on the map and an outline on the minimap, and a vehicle caught inside when the event lands can be destroyed by it. Once it has passed, that patch of the map is different for the rest of the battle: rubble closes a route, an aircraft carcass becomes hard cover, a collapsed wall opens a line that was not there at the start.

Only some maps carry them, and a map that does can carry more than one. They are optional: the Game tab of the settings has a switch that keeps you out of the matchmaker's random-event maps altogether.

They matter to a plan more than their size suggests, precisely because they are uncertain. A position that holds early is not the same position once an event has landed, and a route a push depends on can close while it is under way, so the ground worth committing to is the ground that survives either way.