Since the long-rolling east-northeast waves are starting to break the coasts of Sydney (that is kind of blue dahlia for local surfers), it seems appropriate to study the basic differences between the tides produced by the wind and the bottom surge.
What’s the tricky part
In science terms, tides produced by the wind and the bottom surge are just the same.
Power from the wind is delivered into the ocean when the winds rush over the water face.
On the whole, the more violent the blowing, the more extensive the endurance and the greater the space of the wave generation area is (also known as tide development – the extent of sea area across which the winds fan out), the stronger power is delivered into the ocean and the higher will be the roll of them.
What really counts is the length between the cause of the surge and the point where the surge approaches the land in the shape of breaking waves.
When the surge power pulls itself up and summons up its strength in the course of time and length into a more compelling group, the force of every tide top growths.
It is essential to remember that this build-up in strength may as well result in tides groups being wider apart from each other, creating an unsteady surf weather environment.
Such pattern preconditions the tides’ frequency rhythm that is eventually developed.
What Difference Does It Make for Surf-Riders
Frequency rhythm is basically the time interval in between the waves in a go.
When the surge with a 15-sec frequency rhythm breaks over a reef-rock, standing on the beach you may observe the top of every tide coming in with an equal period of precisely 15 sec.
It’s a mesmerizing scene!
But how the surge frequency rhythm counts for surf-riders actually depends on the wave energy of a certain surge.
This energy is a key factor of differentiation between the waves produced by the wind and those produced by the bottom surge.
Consider two cases of differences:
- Case No. 1: local north-east wind ones are created as a result of high-pressure conditions close to the beachline. The blowing can be powerful but of small duration and the space between the wind cause and the point where break hits is rather small.
Outcome of this difference: Though the outcome may lead to rather moderate waves, the surge frequency rhythm will probably be fairly short, about 8-second interval, and the breaks may be gentler / slowly-paced / smoother (or, as we call them, common waves ), in accordance with the ocean floor peculiarities where the tides crash down.
In this case, and having that difference, breaks may also be influenced by the blowing, taking into account the nearness of the wind cause to the breaks hitting point.
- Case No. 2: let’s recap our long-rolling east-northeast tides that have transformed into a long-interval surge breaking the coasts of Sydney right at this moment (I should gallop through the work and run in for my surf session).
Hank McAdams, the senior specialist on coast watch meteorological predictions, comments on the surge aspects and its differences:
“long-interval ones have developed as a result of the Tropical Cyclone (aka Victor) – the surge of class III was formed across the distant South Seas.
Even though the Cyclone resolves 2500 marine miles far from Australia East Coast, this surge preconditions a few days of medium-size and at times high east-northeast waves over the whole Eastern Shore.
Despite the fact that generation area southward of the hurricane core indicates the wind velocity of 21 to 34 knots, its unhurried movement towards the south is spreading the outstretch of this tide generation area – thus encouraging continuous wave enlargement across the same zone of South-West Pacific Area.
The peak altitude of swell produced by the Cyclone had reached approximately 25 feet height and even amounted to 30 feet height the day after, upon which started to decrease and gradually faded away within 24–48 hours.
The actual benefit and the difference of the Cyclone is its lengthy, unhurried travelling across the South-West Pacific leading to a sustainable set of long-rolling east-northeast waves.
Taking up the lead of an action pattern, the initial impulse is supported by a more considerable session of east-northeast waves – cresting at the height of 4-5 feet inclined to the east-northeast course with a lengthy frequency rhythm of about 16-17 seconds.”
Outcome of difference: As opposed to smoother, gentler, lower waves, this 16-17 sec frequency rhythm of east-northeast surge could develop hard-hitting, wild and smashing waves (once more, the ocean floor is of great importance to the formation of the break).
So, what outlines the distinction between the waves produced by the wind and the bottom surge?
Well, we determined the checkpoint at a 10-sec interval. Medium and lengthy interval bottom surge may outreach a 10-sec interval and short-interval wind surge fail to get to the 10-sec interval.
Another significant distinctive characteristic and difference between the waves produced by the wind and the bottom surge is its cause, which may be contained (as in the first case) or produced over the great distances (as in the second case).
For all that, if a long-interval bottom surge comes to your local beach line bringing rideable waves, you’d better get your surfing kit ready.
