What are the Biggest Disasters Washington State Could Ever Face?

Washington State has always been a relatively safe place to live to avoid certain disasters but there are a few that could still happen. What are the worst disasters that could happen in the State of Washington?

Washington, the Supposedly Safe State

I remember growing up my Grandfather would explain to me how we were safe from most natural and man-made disasters here in the northwest. California had earthquakes, that was before the droughts, and the east coast had hurricanes. Now we now that Washington faces some pretty big disasters, but man-made and natural. What are the biggest disasters that we face here in Washington?