Why are ocean waves measured from the back?

I'm not 100% sure what you mean. Where I surf (east coast) we just eye things. If it looks like 4 feet, we'll say its 4 feet. If you're talking about a stationary pole in the water that is used to measure waves, my guess is that the highest point of the wave occurs closer to the middle of the wave (from the side view).

No Perchick when I was surfin' Hawaii I learned that waves are measured in two methods. "new schcool" which is measuring from the front or "old school" which is measured from the back. The reason for this is when you measure a wave from the front it is bigger and makes it sound better. "Old school' waves that are 6 feet don't make you sound as tough as a "new school" 12 foot wave. If you listen to the surfers report in Kauai' Hawaii they will give the wave height followed by "old school" or "new school".

I would imagine measuring from the back would be harder than front. Perhaps it has to do with the buoys that collect the data.

@gooch. Hence why I said east coast. It's a whole different surf culture.

@ Perchik sorry I didn't know you had waves on the east coast I just thought you were joking. How big do they get....and where can you surf?

There's some good beachs in both south and north carolina, florida...not so much.

Where I surf, folly beach sc, waves are usually 4-6 feet. They actually have a bunch of surf tournaments out there.

Waves are not and cannot be reliably measured from the front or back but only from the side. Hawaiian Scale is actually not wave height but wave amplitude, it measures the distance from sea level to the top of the wave. Wave height is the measurement from the bottom of the wave (which is below sea level) to the top of the wave.