February 07, 2007
Sometimes, you don't need to go further than your own backyard to see enjoy earth science. These whimsical looking cirrus clouds appeared to be playing tag right outside my bedroom window in Glendale, California. In truth, cirrus clouds form at altitudes above 20,000 ft (~6,000 m). Their wispy appearance is due to the strong wind currents (and wind sheer) occurring at these altitudes. These winds quite often form waves, and in moist but stable air layers, clouds will take shape along the crests of the waves. Cirrus are composed of ice crystals -- temperatures at these heights are generally below -38 degrees C (-36.5 F). Photo taken on October 23, 2006.