Mammatus (w-435-25)

In gallery: Photos of the month (2002)
Related photos: Clouds Severe weather Mammatus

Big mammatus forms under the anvil of a severe storm in southwest Oklahoma, USA on May 24. Note the bright blue color between the mammatus pouches; this transmission effect was even more striking in reality.

Praktica MTL, Fuji Sensia 100 film, 28mm Sigma zoomlens.