It’s a befeirush gemara that “Ain Puranus ba LaOlam ela…”.
That doesn’t mean we know why Hashem brought this or any other storm. But Chazal have already informed us of the general principle.
It’s also interesting that you mention your “theory” after this particular storm, which was unprecedented and was a “perfect storm”, not a “typical” storm, and therefore was that much more “miraculous”.