Why do tsunamis (20~ft) cause more damage and flooding than the waves that surfers surf (world record 86ft)?

Question

Why do tsunamis (20~ft) cause more damage and flooding than the waves that surfers surf (world record 86ft)?

In: 2

Answer 1

There was some amazing side-on footage of the japanese tsunami, where in front of the wave the water looked at a roughly normal level. The wave itself was probably only 1-2m high. But behind the wave, the water was totally flat…. just at the new increased height of 1-2m.

And the whole lot, that went as far as the eye could see, was all rolling towards land at speed.

Imagine that hitting land, and just having so much moving weight it just wouldn’t stop.