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Phuket Surf Report and Forecast
 



How big is a wave?
How do I measure a wave's height?

Saltwater Dreaming is very aware of the constant confusion about how you should measure the size of a wave. For Hawaii and and a lot of older surfers the wave is measured from the back, making a wave that is 6 foot high at the front being 3 feet. This over the years has created great confusion and controversy.

  • Therefore to help create some sort of standard this web page will use the front, or face of the wave as the measurement. If a surfer is 6 feet tall a 6 feet wave will be head height.

  • Noted by one of our visitors another variance is where the wave is breaking on a shallow reef break, this can make the wave jack-up to twice its original height. Another visitor also added that we ride the face of the wave and so that's where we should measure it from.

  • Steve from Victoria Australia says "Where I come from (Jan Juc Victoria (near Bells)), we normally give two measurements: swell size and wave size. The swell size is where you refer to the "back" of the wave, and the wave size is the size of the face just at breaking point.

    For an example, a little known right hand point wave in the area, the wave size actually gets bigger as you surf it due to the shape of the underlying reef. For example on a 3 foot SWELL SIZE, you take off on a 5 foot WAVE FACE. But by the end of the rdie, as the reef gets shallower, the wave can jack up to 8 foot face size.

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  • E. B. says "I personally talk face of waves. The whole stupid back measuring way started out due to selfish lifeguards on the hawaiian north shore (http://web.onetel.com/~simonathey/waves.htm) personally i just think everyone should go back to talking face because back is just stupid"

  • Johrdan says....I believe it should be the face of the wave, too. It is obvious that it should be the front. We don't ride tha back of the wave now do we. Why the need of complications, THE FRONT DAMN IT!!!

  • Ted now living in serene Phuket says.....I am from Hawaii (surfed there for 50 years) and I dont know anyone who would seriously call a twelve foot wave one has just rode, as six feet. They would say.....how big? It was Double over head man!! Its the face of the breaking wave that we measure, not the ocean swell before it breaks.

  • Chunks says Bwaaaahhhahahahahahahahah. Here (Aust) we tend to talk the wave size down. I'd look like a cock if I went up to my mates raving about 12ft surf when it is only 6ft.

    Maybe beginners like yourselves need to seem like hellmen by talking up the waves, god knows if it was constantly 3 ft here I too would be tempted to say it was 6ft but ITS NOT.

    We talk of the swell size ie. 2.5m SE open sea swell will produce 4ft at a southern point and maybe 6ft on a northern beach and more like 8ft a bit further down the coast so its all bullshit.

    If I say 6ft Dbah it is understood that Dbah on a 6ft swell may produce a 15ft face.

    To me its either on or its not and I can tell how the swell has been by the size of the smile on me mates face when they are telling me of their war stories. If they say its 45ft then it fucking well is.

    Instead of worrying about it all why dont you just go and get fucking tubed fuckwits.

    seems like Chunks is a cool guy you can send feedback to him here sendmailtotimmo@yahoo.co.uk ????? an Aussie with a UK address???

  • Maaaaaaaaaaate!!!!!!!!!
    Who cares how big the waves are if you come out of the water stoked with your last surf session..........
    At the end of the day its the size of your balls that will indicate what size you actually go out in and surf.....................
    ALMAGA

  • I think that measuring the back of a breaking wave is possible but meaningless. Hollow waves will have a smaller back but a bigger face, whereas the face and back of a mushy wave will be almost identical. I can surf the backs of waves with a kite, and also use the energy on the back while paddling outrigger canoes, but as a previous guy said, a lot depends on the reef (or sand) underneath and "real" surfing is done on the face. The other issue is one seldom stated: swell period. Long swells are faster, carry a great deal more water, and have exponentially more power. An 18 second period swell in Hawai'i or West Oz will have vastly more power than an 8 second period wind swell in Thailand even if the wave height is the same.
    Felix - California/Thailand


  • Being a 1st class honours mechanical engineer, having done PhD in Wakes created by ships and having surfed 12 ft Ulus and 8ft Macaronis, I probably know a bit more than most in this area. I propose a quantitative measure that will be the closest measurement possible to reflect "Gnarlyness" of a wave.

    (Swell Period)*pi*e^(face wave height))/(Back wave height)^.5

    I hear by call this formulae the Banks Wave Index.

    Roderick-Australia

  • Click here and give your opinion on wave measurements and heights.

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