  The shape of clouds has proven to be essential for classifying them. Our
analysis of images from fair weather cumulus clouds reveals that, besides by
turbulence they are driven by self-organized criticality (SOC). Our
observations yield exponents that support the fact the clouds, when projected
to two dimensions (2D), exhibit conformal symmetry compatible with $c=-2$
conformal field theory (CFT), in contrast to 2D turbulence which has $c=0$ CFT.
By using a combination of the Navier-Stokes equation, diffusion equations and a
coupled map lattice (CML) we successfully simulated cloud formation, and
obtained the same exponents.
