[PapaBear3625]

I think his point is that the astroid is no longer a solid with a core - if correct, then as it enters the atmosphere it will begin to break up and burn easier than had it remained solid.

If it breaks up in the upper atmosphere, it will do less damage than if it stays solid enough to hit the ground, but that's still a lot of energy. Some of that will reach the ground in the form of concussion and heat, and you will have dust in the upper atmosphere affecting the weather for a long time.

The 2013 Chelyabinsk meteor was just 20 meters wide, and released the equivalent energy of a 400-500 kiloton nuke.

[Ozark Tom]

A close packed fragment blast is not better than a solid mas ground impact. The down migrating shock wave would be more potent. A larger plasma plume would blast back to higher altitude. Line-of-sight for heat flash effects is extended.