Let's be honest: it's highly unlikely (basically impossible) that what was depicted in this manga could happen in real life (in the same way, at least), we all know that. But again, this is a manga, so...whatever. Also the mangaka needed a fire, and this was the first thing he could think of. Maybe he heard that in particular (exceptional even!) conditions something like this could happen, but that doesn't mean it's plausible. Also, in Tokyo, in october, temperatures are way lower than august, so I think what was shown in the manga is simply impossibile.