Thanks for explaining this. I was also familiar with the ‘doubling up’ effect and figured rogue waves were just the unlikely result of multiple double-ups that happen to line up just so. As a surfer you get used to seeing ‘bombs’ once a session or so that are 50-100% bigger than typical set waves (which are already bigger than the average waves). It wouldn’t seem much of a stretch from there to expect that two of those bombs could find each other and double up now and then, and from there that two of those super-bombs would double up every once in awhile.

It’s interesting to know that they happen a lot more often than would be expected statistically from those simple mechanics. Yet another fun potential rare event to keep in mind while surfing in Northern California :)