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Cloud Streets

By: Dr. Jeff Masters, 2:37 PM GMT on April 24, 2005

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!

Clouds Streets
Clouds Streets
Regular "roll" eddies of interlocking rising and sinking thermals give rise to these remarkably organized cloud streets.

Atmospheric Phenomena

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

I remember seeing those on numerous days early in the morning from the drill field at Lackland AFB, Texas, way back in the summer of 1965. Couldn't help but think that they looked like us as we learned how to march in formation.
I live on the Pawnee Nat. Grassland in NE Colorado, and I see cloud streets very often in the summer. I will try to remember to send some pictures when they come back this year.
Clouds of ANY sort are so cool (no pun intended.)

When I fly friends, it's pretty easy to impress them when one can predict the "speed bumps" in the air when passing under cloud ridges and then back into sunny air.

Jeff, do you have an estimate or knowledge of the altitude those formations are at? They look relatively low (4000agl?) Those would be fun to fly under and perpendicular... bump bump bump.... I wonder how the Glider pilots would use those...