Any: conventional, nuclear, or impact can cause a mushroom cloud.
A nuclear detination
Surface burst
A shallow subsurface burst.
Surface
surface burst
shallow subsurface
Surface Burst
surface burst
Surface burst
shallow subsurface
Surface burts
A low altitude detonation or a groundburst will cause a crater to form. Nuclear detonations that take place near the ground (but not underground) will create a mushroom cloud (this is caused by a Raleigh-Taylor instability). I have noted that a lower level detonation close to the ground will suck up material into the fireball and create a more pronounced stem.