It's back, like a cold sore. Nazaré Canyon. The wave that sometimes isn't a wave because a wave has a crest and a trough, and Nazaré often lacks the latter. The hype that comes with it is back too. "Biggest wave ever ridden?" "The 100-foot wave?" "I'm Ron Burgandy?" Those question marks express doubt, and rightfully so. It's like a surfers version of a cheap philosophical question: If a wave breaks without a bottom, does it break a world record?

It stirs up a bigger question of how we measure waves, and the inevitable pitfalls flaws we run into in the process. A wave is measured as the vertical distance between the crest and the trough. Find the bottom. Find the top. Measure the distance. Should be easy. But when you're looking at a wave straight on, especially from elevation, things can get tricky.

Nazaré Canyon is a caricature of this phenomena . At steep waves like Jaws or Maverick's you can see that the lip is almost directly above the trough (or at least is in the frame). But at Nazaré, because the wave is so flat, the distance between the lip and the bottom of the wave might be a 100 feet long, while the wave height is actually more around 60 feet. See the above example of Carlos Burle's wave at Nazaré on October 28. At first glance it's the biggest wave ever ridden (or at least as big as either of Garrett's from the same wave and same camera angle). The wave looks 100 feet because we're seeing about 100 feet of face in the image, but that face isn't vertical. Far from it. This is shown in the following graph, which illustrates a virtual cross cut of this wave.

When looking at waves from the side, like Alain Rioui’s wave at Belharra below, you can easily draw a vertical line from the bottom of the wave to meet a horizontal line drawn from the crest of the wave and measure the height that way. But that becomes impossible when you're looking at a wave photographed from the front, because even if you found the bottom of the wave (a subjective location in most photographs), you can't draw the horizontal line from the crest of the wave toward the bottom because you'd be entering a third dimension that a 2D photograph doesn't allow.

What lessons can we take away?

1) Nazaré is a place where giant swells are ridden, but these aren't 100-foot waves.
2) The wave is dangerous, as we saw with Maya's broken ankle-to near drowning-combo.
3) We need a better way to measure waves, especially when they're photographed from the front. If anyone is knows of any special technology, software or math that is available that might help with something like this, we'd love to hear about it. Leave your suggestions in the comments section below or email me at taylor@surfingmagazine.com.

—Taylor Paul