Its been revealed to be deflated because you overlooked Doof’s statement, where he says it weighs 2 tons, and you the one got is <2500x the actual weight. Are you intending to recalc it, but with the part of the building was destroyed instead of the KE of the tin foil ball?
It seems questionable that he was the one causing the storm. It could just be the result of him, who is currently dead, coming back briefly enough to fight her. Even if it was him who caused it, it most likely is Environmental Destruction, since he never uses that power or energy to attack her. It'd also be a possible outlier considering the rest of the students and teachers have several tier 8 feats.
I would suggest asking TheRustyOne what he thinks, though, just to get a second opinion.
"it's very questionable that he was the one causing it"
It literally happens because of his aura, and the storm goes away as soon as Kurokage disappears. It can't be more obvious that it's his doing.
"he never attacked her with said lightning"
Lightning isn't necessary to scale, as the energy of a single bolt of lightning is only around Building level. In order to scale, she only needed to fight evenly against someone whose sheer power had caused the storm to happen, which is what's happening in this fight.
"are you sure it's not just environment destruction?"
This kind of argument only works for things like floods or things that are just being summoned without being connected to one's power and not naturally caused because of a person's sheer power.
I really think it's Environmental Destruction. ED doesn't just apply to floods; it can apply to any "feat" like this where they don't use these powers to attack people.
Also there are a few Tier 8 feats for the series and this would be the only Tier 7, which is much higher than the rest of the feats for the students/teachers. So in other words, it seems like an outlier.
It's also likely that Kurokage was holding back; I doubt he'd go all out on his own granddaughter.
I think you're missing the point if you think that going all out matters in this context, because Kurokage is clearly taking the fight seriously enough to cause the storm in the first place. Plus, taking the context of the scene into consideration, there's no reason to believe that he is holding back, because he's already a spirit and wanted to see Yumi's true power before passing away completely. And about the claims regarding the feat being an outlier: There are at least three feats that are comparable or higher. -In the opening of Deep Crimson, the scrolls are shown dispersing a massive storm. This hasn't been calced but it would be around City, possibly higher. The scrolls are what power the shinobi, so it would scale. -Kagura can completely wipe out Kyoto in Deep Crimson. This was calced to be around Island level. Granted, this feat only applies to the top tiers of the verse, but it is still a higher feat that invalidates the idea of it being an outlier. -In Estival Versus, Jasmine is responsible for the creation of a world vast enough to have continents, which were destroyed by the Shin Yōma, which Jasmine defeated. All the characters in the cast are able to fight against Jasmine, but this is a feat that I would consider too outlierish to scale to everyone, given that it's higher than what even Kagura has done.
I know it kinda sounds like i'm trying to start a debate, but I'm just trying to explain why it's rediculous to him and I just wanna explain why it doesn't make sense.
I think you're missing the point if you think that going all out matters in this context, because Kurokage is clearly taking the fight seriously enough to cause the storm in the first place.
Even if it is him causing the storm, it could just be a scene change or him showing off his power. Plus, he never uses lightning or anything from the storm to attack, and that's usually what separates ED from not ED. It could just be that the weather changing is a result of an ability he has (i.e. Weather Manipulation) and not a result of his physical ability.
Plus, taking the context of the scene into consideration, there's no reason to believe that he is holding back, because he's already a spirit and wanted to see Yumi's true power before passing away completely.
There is actually reason for him to hold back. He wouldn't want to seriously injure or kill his own granddaughter. It's likely he held back just enough to challenge Yumi and force her to prove herself without making it impossible for her to put up a fight.
In regards to the Deep Crimson cloud clearing feat, it's questionable that it's the scrolls causing it. First of all, there's a cut between when Asuka pulls the scroll out of her, well, cleavage, and when the cloud clearing happens. Additionally, the light that comes from the scroll is yellow while the column of light or energy or whatever that shoots into the sky and clears the clouds is red. That beam that clears the clouds is actually reminiscent of the color scheme of Kagura's attacks.