Cloud Streets

Something all wunderphotographers should be on the lookout for is cloud streets. These long lines of parallel cumulus clouds can form on a sunny day over a flat region. Solar heating causes a thermal "bubble" of air to rise until the air cools to its dewpoint temperature, at which point a cloud forms. The rising air then spreads out and sinks back to the ground on either side of the cloud, creating a cloud free area, since the air warms as it descends, evaporating any cloud moisture within it. Over a flat, homogeneous area, a long series of interlocking sets of thermals can somtimes organize, leading to a large "neighborhood" of cloud streets oriented parallel to the wind direction.

If anyone can find an example of cloud streets in the wunderphotos, please post a comment with a link!