Bears, Wolves and Anticrepuscular Rays
November 14, 2007
Unfortunately, I do not have a picture of the wolves and bears! On vacation in Yellowstone National Park in the middle of June this year, my wife and I had joined a gathering of about twenty people on the side of the road who were studying distant wildlife through powerful telescopes and binoculars. It was just after sunset, but on being invited to share the view, we saw, on one side of the road, a wolf dining on a bison carcass. On the other side of the road, up a hillside, a pack of wolves had distracted a brown bear sufficiently to capture and make off with her two cubs; both the distressed mother bear and one of the wolves were clearly visible though the telescope. All of a sudden, I gazed up into the eastern sky and saw these magnificent anticrepuscular rays. I drew attention to them, and most of the group was quite impressed with this wonderful display before returning to the task at hand! These rays are shadow bands produced by clouds in the west partially blocking light from the sun. They're most commonly seen as crepuscular rays emanating from the sun's location, even after it has set, but on this particular evening, only their extension in the east was visible. These rays appear to converge at the antisolar point; but since they are parallel, this is merely an effect of perspective. Meanwhile, in the western sky, a beautiful sunset was also vying for our attention.