Sonoran Desert - Monsoon Thunderstorm

During a good monsoon season thunderstorms can be seen several times a week, though they occur overhead much less often because most cover only a few square miles. Tucson is widely regarded as the lightning capital of the world. Many other areas have more lightning, but in the desert it is more visible. The ground elevation here is about 2000 feet (600 m) while the cloud bases in the relatively dry atmosphere are usually at 10,000 feet (3000 m), so lightning bolts zigzag through two to four miles (3 to 6 km) of clear air.

Top image: view from the Tucson Mountains across northwest Tucson to the Santa Catalina Mountains.
Bottom: An approaching evening storm just before the rain (purplish haze) arrives.