I've attached a link to a great article on sailing through a Tsunami, a waterspout, Asteroid Strikes etc. This is well written a pretty funny.
48° North - Severe Weather Sailing
I ONLY PUT THAT TITLE THERE TO GET SOME ATTENTION TO ARTICLE I LINKED ABOVE. Any wave that is too big for your boat is trouble. I've had a night in 20+ seas which we handled well enough, except for the fact that there is a pretty well documented phenomenon of a periodic or rougue or whatever you want to call them that happens often enough, about every hour. When you think you are doing just fine then all of a sudden the big waves get BIGGER or start BREAKING and if you don't adjust real quick, FUN WOW!!! Next morning was a Sleigh Ride but still experiencing some pretty big waves.
YouTube - 25-30 Knot Winds 31N 79W 10-20 foot seas