What are hurricane-generated waves?


Big wave surfers are storm chasers. They travel the world in search of the largest swells. But what exactly are hurricane-generated waves?

Science tells us that the barometric pressure in the eye of the hurricane is lower than the pressure some distance from the eye. Hurricanes are also known as tropical cyclones because they form primarily in the tropics. Asians call them typhoons.
High wind speeds associated with hurricanes are able to produce extreme waves. When water rises from the eye of the hurricane and gets influenced by winds, currents and tides, a storm surge is in the making.
In other words, there's a dramatic increase in the water surface elevation at the coast by tens of feet, causing destruction in the coastal region.
"The waves generated by a hurricane differ from those generated by normal wind conditions in several ways. The speeds of the wind in the hurricane aren't constant, so the wave characteristics vary," explains Frederic Raichlen, author of the must-have book "Waves".
"The winds in a hurricane have a circular path. The hurricane moves over waves generated at various angles of direction to the storm path. To the right of the eye (in the northern hemisphere), the winds are enhanced by the forward speed of the hurricane increasing wind speed from simply that of the rotating wind system."
"Because the storm surge increases the water's depth near the shore, the waves generated by the wind can now propagate on deeper water, and larger waves and wave breaking can occur nearer to the shore than would occur without the hurricane."
Weather forecasters have scientific methods for predicting hurricane-induced waves in deep water. The following guide is based on observations, and it should not be considered absolutely exact.
Category
(Saffir-Simpson Hurricane Scale)
1
2
3
4
5
Wind Speed
(Kilometers per Hour)
119-153
154-177
178-209
210-249
>249
Wind Speed
(Miles per Hour)
74-95
96-110
111-130
131-155
>155
Wave Height Range
(Meters)
4-8
6-10
10-14
10-14
12-17
Wave Period
(Seconds)
7-11
9-12
12-15
12-15
13-17

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