They will thaw and hop away the next spring. Honks in the air draw the girl's attention to the sky, which is clear and blue because air molecules in the atmosphere scatter blue light. Autumn skies in Alaska are a deeper blue than spring skies for two reasons. Snow covering the ground in springtime reflects about 90 percent of the light that hits it. Air molecules scatter the reflected sunlight again, washing away a bit of the blue.
Fall skies are also free of arctic haze, a wave of pollution from Eastern Europe and Asia.
The particles that make up arctic haze, which shows up in spring, don't scatter blue light as easily as the pure air of autumn. The little girl watches as Canada geese fly in a V formation, leaving the rich breeding grounds of the Arctic for warmer places. Scientists who study flying geese found that a flock of 25 birds in a V can fly 70 percent farther than a single bird using the same amount of energy. In a well-formed V, even the bird at the front receives a benefit from its neighbors. As the girl turns to walk home, she catches the musky smell of fall coming from highbush cranberries.