How are tsunamis crashing through cities and wiping out actors filmed?

Question

In the movie The Day After Tomorrow (2004), there is a city (much like a modern day city) and during a natural disaster; there is a Tsunami that crashed through the city, destroyed buildings, killed many people on the run, overturned cars etc. I believe it may be some form of CGI, but I am not sure because buildings and stuff are being destroyed by it. So I am not sure.

Answer 1

It ultimately depends on the production. It's becoming more common that they're entirely VFX (the official term for CGI in film), but some productions have used and still use miniatures, composite shots of real locations and actors, and special effects (the term for explosions, waterworks, etc.) to recreate the effect.