It was 18 F. and partly-sunny when we left home for Tortugas Mountain this morning, but as we neared the trailhead on the west side a heavy fog settled over the area. For a while it looked as if it would lift, but it only got denser. When the wind picked up--about 2/3 of the way into the hike--it got quite cold. There were a few other people braving the elements: a man and woman with a dog each, a man with two dogs, a jogger, and Greg, who we saw back at the parking lot just as we were leaving. He was setting off for the top of the mountain.