SOUTHWESTERN STATES

Double Rainbow Sunsets, Sunrises, and Rainbows

The frequently clear skies over the desert portions of the Southwest create excellent visibility, allowing opportunities to view many optical phenomena in the sky. Some of the most spectacular and most common displays are sunrises, sunsets, and rainbows. Sunrises and sunsets frequently exhibit vivid colors as the low-altitude light travels through clear, dry air. Rainbows are observable when you stand between the low-altitude sun and a raining cloud; in deserts, they regularly occur in the late afternoon and early evening. Rainbows are particularly intense after heavy rains, when they often exhibit both primary and secondary arcs, a phenomenon called a double rainbow.

PHOTO: Tom Till