No you don't. And if you think you do, I advice you to camp a couple weeks (legal limit) at camp muir in a stormy period of winter. And do that a few times a season just to get a taste of it.
Pretty impressive to compare the ECMWF metoegrams from today's 0z vs the 18z. For Wednesday it went from 54/45 for SEA on the 0z to 51/39 on the 18z. Like the trend!