The photo above shows a set of splendid crepuscular rays taken at sunset near Van Buren, Arkansas. These rays resulted from cloud formations just above the observer’s horizon. In general, the more remarkable the sunbeam and shadow lanes, the more obtrusive the clouds creating them. Photographer: Mike Holloway
A thunderstorm (cumulonimbus cloud) near the horizon will block out more sunlight than a fair-weather cumulus cloud (cumulus mediocris). Here, the Sun has set directly behind the flat-topped cloud (anvil) at bottom center. Cloud turrets behind this anvil likely account for the sawtooth nature of the rays. Photo taken on September 7, 2011.