Why do tidal waves or tsunamis in real life not look like the huge waves in the movies?


Whenever there’s a tsunami in the movies it’s always a 100 foot tall wall of water instead of the rolling waves we see in real life. Could a wave actually get that high and make it to land?

In: 3

The big breaking waves you see in the movies or more often in surfing videos are the result of various, but extremely specific sea floor geography. Those conditions just don’t exist on most sea shores around the world. That’s why surfers travel to the areas with big waves, not just their nearest coast.

See the force of waves is almost entirely lateral. The things that cause them to curl over and break is either the wind behind the wave pushing it over or the sea floor redirecting the energy up at such an angle that it creates a narrow but tall wave. Again those sea floor conditions just don’t exist most places. So tsunamis just end up being really wide and short waves.

Because movies are make-believe, made by people who have never seen a tsunami, who don’t care that other people have, and who don’t know how to make a real tsunami look interesting within the bounds of their portion of the production budget.

Movies are not reality.

Movies have gigantic thousand-foot-tall waves because they look cool in movies.

Tsunami’s generally involve the whole water column as part of the wave. The normal waves you see are surface waves, and as the name inplies are only on top of the water column.

The wavelength of a tsunamis is MUCH greater than that of a surface wave. In open water the wavelength of the tsunami can be hundreds of km while a surface wave has a wavelength of a few 10’s of meters.

Instead of stacking up, a tsunami “stacks long”. It may be a short wave (height wise), but it keeps coming and coming and coming because it has such a long wavelength.

As everyone else says, a tall wall of water is much more photogenic/cinematic and scares people–probably because people have plenty of experience with surface wave with very few having experience with an actual tsunami.

> Could a wave actually get that high and make it to land?

[Yes](https://www.youtube.com/watch?v=pZTx0XBx4hk). But these aren’t tsunamis.

Tsunamis are as damaging as they are not because of their height but because of their length. A tsunami can have a wavelength of hundreds of kilometers, so there is a huge amount of water behind it unlike a normal wave that breaks and dissipates when it hits land, a tsunami behaves more like a rapidly rising tide (hence why they’re sometimes known as “tidal waves”).

Note that tsunamis triggered by landslides rather than seismic activity can be *much* larger. In 1958, a landslide in Lituya Bay, Alaska, triggered a megatsunami that caused damage 524m (1719ft) above the waterline. This is higher than the Empire State building. Such an event has, as far as I’m aware, never been filmed, so who knows what it would look like.