dark cloudsFirst, dark clouds begin to boil in the sky, and lightning starts to crackle and fizz.
cloud of dust
storm cloudsGlancing up at the sky, she saw the storm clouds gathering on the horizon.
cloud of smoke
grey cloudsThe wind began to pick up strongly; dense grey clouds skidded across the sky.
through the cloudsHe stepped out into the square and lit his pipe just as a watery sun broke through the clouds.
black cloudsHuge, black clouds rushed on the horizon.