Cumulus Congestus
This was part of a very strange storm: a SSW-ward right-moving member of a supercell split, in northwesterly mean flow, with two rear flanks, and splitting for a second time at the time of the photo. It was a fascinating process to witness! A large amount of rusty dust was being entrained in the updraft, thus the yellow/red tinge in the lower middle. The balcony of convection in the middle was rolling over on itself as the towers shot up through it.
11 W Roll OK (20 Apr 89) looking ESE.