Why are the waves around Hawaii and Australia so high?

Answer 1

There are a number of reasons, two of them include the fetch and bathmetry.

If a wave has a long fetch that means it is likely to be larger, the fetch is, in simple terms, how far the wave as traveled from its propagation or source to say the coast where you see it break over the shore line. Say for example a wave breaks on the coast of Hawaii, Hawaii is many many miles from another landmass, that means that the wave has traveled in the ocean for many miles allowing it to grow in size which means it'll be bigger when it hits the shore line; this is helped by the strength and direction of the wind too.

Another factor is bathymetry or simply what the surface of the ground is like under the water, as the surface of ground under the water slopes upwards to the shore line when the wave comes towards the land it rubs on the ground and this friction causes the front of the wave to slow down, because it rubs on the ground first, and the back part of the wave catches up with the front and tries to over take it, causing the wave to get taller, the steeper the ground the more quickly the front part of the wave will slow down and the back part will catch up making the wave get taller more quickly. Bathymetry can also funnel the waves in different ways into different shaped bays and coves etc which can slow them down or focus the energy into a more confined space which could make them higher.

Answer 2

Waves around Hawaii and Australia can be high due to their geographical locations in relation to prevailing winds and ocean currents, which can create large swells. These regions are also prone to powerful storm systems that can generate large waves. Additionally, the large expanses of open ocean surrounding these areas allow waves to build and travel long distances before reaching the coastline.

Answer 3

because of the currents