ive seen a few videos now claiming 77ft , 85ft and now 90ft. I just dont see how they can measure something accurately that is moving and without a
tape measure.
this one is claiming 85ft
edit on 9-11-2011 by PhoenixOD because: (no reason given)
Wave height is actually measured at the back instead of the face of the wave.
I learned this from my many summers in the Junior Lifeguard program in Huntington Beach way back when.
This seems to be a common misconception, and I think it stems from the size of the swell being smaller than the size of the wave face when it breaks.
Swell size is the amplitude of a wave in the open ocean. However, once that swell hits shallower water, it can grow in size and shape depending on
the ocean floor topography. A 3 ft swell, can break with a 5-6 ft face under some conditions.
Measuring a wave from the back is not a useful way to measure waves, as different types of waves have different shapes and some massive waves have
almost no back to them. A good example is Teahupoo in Tahiti, known as the worlds heaviest wave, yet it has almost no back to the wave whatsoever due
to the way it breaks over a very shallow reef from very deep water. The wave in the OP and other waves such as Jaws gradually build up over deeper
reefs and have a much bigger back, even for the same size wave face. Therefore wave face is generally measured from the face of the wave,
which can be a lot bigger than the size of the swell that produced it. Wave face measurements can sometimes be estimated by using the height
of a surfer as a reference.
Here's a clip of the big wave highlights from the southern hemisphere from the last 6 months, with waves from Teahupoo-Tahiti, Cloudbread-Fiji and
Shipstern Bluff in Tasmania. Some of these waves are known as slabs, which are waves which barrell and break with a thick lip, without neceassarily
having high wave faces. Enjoy.
That was an interesting read. But I must say, none of the surfers I know use the "back of the wave" method, and I didn't realise many peopl used
it, for the given reasons that it is not very accurate. There is a lot of debate on wave measurements, but generally here in NZ (and Australia), the
swell size is used to describe wave size, and different breaks will have different wave faces for a given swell size. That's why surf of 4
ft, can break "overhead" for a 6 ft man. But I guess there's no set method, so anything goes really
I agree.
For the purposes of the largest wave award they do use the trough to crest height. Gotta use something I suppose but it doesn't really tell you much
about the mass of the wave (of course a 90 foot anything is pretty enormous).
I still can't shake the "Hawaiian" method of calling wave heights. Rather than representing the face of the wave, it's more a matter of the height
of the crest above sea level. This makes it less dependent on the character the wave. A wave which breaks in relatively shallow water draws a lot of
water off of the reef creating a trough in front of the wave while a deep water wave doesn't have the same effect. Look at it this way; the drop on a
six foot wave at Pipeline is a bigger deal than a eight foot wave at Sunset. So, if the forecast calls for eight feet in the country it really depends
on which spot you end up at. Sunset will be fun but Pipeline will be getting spooky.