February 17, 2008
Grand Mammus
In all seriousness, I believe these are called mammus clouds. We've seen them here last spring. In fact, you'll be pleased to know that, while searching for that photo, I put together a thread of some of the cloud photos we've featured here in the past. Aren't you just ecstatic?

*Harvest View
*Best of Today
*Wayback Machine
*How Do I?
*Today in History
*Calvin and Hobbes