I went to a party tonight, and when I got back I decided I might as well shovel, since I was all bundled up and outside anyway. The dogs knew someone was outside, but they didn't bark until I was walking back past the side of the house. I paused, and Lannie spotted me first. She started barking, with her teeth bared. Sophie joined in, but as I moved closer to the window, she recognized me, and I could hear her barking change to just barking because Lannie was.
And what was Leo doing? He was sitting on the window seat, his back to me, deliberately not looking out. And not barking, though he clearly knew there was something Very Bad outside the window. I tapped on the glass and he leaped off the seat and ran across the room, paused, looked over, and ran up the stairs, his tail tucked.