11.   The weather was overcast, with heavy low clouds.

12.   While they slept, heavy clouds swirled over the valley in massed ranks and the snow began to fall.

13.   Our plane broke through some heavy low clouds during its ascent and leveled off once we were above them.

14.   Clouds heavy with rain over Herefordshire.

15.   And several days later, as heavy clouds moved in over the combat zone, most air operations were canceled.

16.   Any surplus generated power is stored in batteries that supply current for night use and times of heavy cloud cover.

17.   Between Iwo and the Japanese capital, storm fronts brought heavy clouds, strong wind, pounding rain.

18.   A star emerges from the collapse of a heavy molecular cloud.

19.   But heavy gray clouds obscured any view beyond the dark green foothills of the lush, wide valley of Lijiang.

20.   But that dull gray paint on the crutches is cracking, like heavy clouds fragmenting after a storm.