mushroom cloud
A large distinctive mushroom-shaped cloud of debris/smoke and commonly water vapor from a large-scale scale explosion.
Most commonly associated with nuclear weapons, but can also be caused by conventional explosives of significant power and natural events like certain types of volcanic eruptions and impact events.
If the explosion were implied to be caused by nuclear device, or that the typical characteristic of nuclear explosion were present (such as superheated atmosphere), also apply the tag nuclear explosion.