As the water depth decreases, the tsunami speed decreases.

However, the wave's energy flux remains nearly constant.

Consequently, its height grows.

Because of the shoaling effect, a tsunami, imperceptible at sea, may grow to several meters or more in height near the coast.

When it finally reaches the coast, a tsunami may appear as a rapidly rising or falling tide, a series of breaking waves, or even a bore.

Tsunamis can reach the coast with tremendous amounts of energy.

They can move inland several hundred feet, crushing homes and other structures.