Tsunamis have really long wavelengths (100s of km). For a wave to break, they must reach a height that is 1/7th of the wavelength. That would require a height of 10s of km to break. Obviously that does not happen, so tsunamis do not become breaking waves and instead roll up on shore.
A breaking wave is much for dramatic so movies opt for that
-PS5 t1_je7bjb3 wrote
Reply to ELI5 Why do tidal waves or tsunamis in real life not look like the huge waves in the movies? by ColonyLeader
That's because the movies are unrealistic!
Tsunamis have really long wavelengths (100s of km). For a wave to break, they must reach a height that is 1/7th of the wavelength. That would require a height of 10s of km to break. Obviously that does not happen, so tsunamis do not become breaking waves and instead roll up on shore.
A breaking wave is much for dramatic so movies opt for that