We were just talking about significant one third highest wave heights and how this compares to what you may encounter. The graphic above and photo below are  a partial explanation from Mariner’s Weather Handbook (the link will take you to the table of contents)

The bottom line is that the very highest waves can be twice the significant highest 1/3, in other words, big. But as the photo above shows, these really big waves are transitory and rarely occur over long distances. With maneuverability, and good boat speed, if you are alert it is sometimes possible to get out of the way.. For more on wave probability see page 244 in Mariner’s Weather Handbook. The section on the Sydney Hobart Race 1998 storm has some amazing data on using maneuverability to get out  of the way of huge breaking seas.