Weather rarely gets that bad that quickly
I have seen this phenomena on a couple of occasions, once off the shore in Long Beach, CA and once off the shore in Scotland. Steam suddenly starts rising from the sea and within minutes has drifted over the land, a sea harr I think it is called.
I was playing golf on one occasion and could see the fog coming towards me and could see nothing withn about 2 mins from when I first saw the steam rising from the ocean. I could hear a little plane circling above and for once I was happy to be on the ground.