The problem of the flood exists not just in the time of Noah.
To be sure, God promised that there would never again be such a flood of water, but as any good lawyer would point out, He never promised to desist from other floods.
God’s promise is, in this respect, a carefully-termed legal clause, complete with limitations.
In fact, there is a flood in almost every generation.
In some generations, the “flood” is physical; it may be a wildfire, a tsunami, an earthquake, or a volcanic eruption.
In other generations, the flood is not physical but spiritual.
Just as a physical flood may involve water falling down from heaven or surging up from the sea, in a spiritual flood the intellectuals inundate us with anti-religious messages from above, and from below, the masses initiate a deluge of dissatisfaction with the religious experience.
Hence, the need arises to build an ark.
For this reason, people gather together and safeguard themselves; they build for themselves walls so as not to drown in the ocean of water.
On the other hand, the story of Noah should remind us that even someone who is saved from the flood can end up like a drunkard, leading an insular life even in spiritual matters; and then the world will have to wait another ten generations until someone comes along to save it.
–Rabbi Adin Steinsaltz
From Talks on the Parasha