Did a dive trip to Cortez Banks a couple of years ago. Cortez Banks is the Southern California equivalent to Mavericks in NorCal. Cortez is an offshore seamount; maybe a square mile in area, but only about 10 percent of that or so is shallow enough to dive (recreationally, anyway.) The shallow point is about 15 feet. The guys that surf there are usually ferried out to the area on big boats, then use the jetski tow-in a la the video.
The days we were there, there was a 16 to 18 foot swell, but with nearly a minute period (made for some impressive surge, even down to 100 feet.)
We were anchored for the night about 1/4 mile from the high point, and we could watch the swell build as it approached that point. All told, you ended up with about a 60 foot mountain of water out in the middle of nowhere. Pretty eerie.