21.   Both towers partly disappeared behind thick clouds of dark smoke, then the top floors of the south tower began to fall, leaving only black smoke.

22.   A cold front stretching from south Texas to low pressure in eastern Wisconsin will mark the leading edge of thick clouds and showers.

23.   A combination of an active breeze and thick clouds helped keep readings well above seasonal levels.

24.   A stalled front from Florida to Texas will be the focus of thick clouds and showers.

25.   A thick cloud cover is expected over this region with light snow likely from eastern Minnesota to central Michigan.

26.   Brisk breezes from the north will combine with patches of rain and thick cloud cover to enhance the chill in Iowa and eastern South Dakota.

27.   But it got away in time to beat an approaching bank of thick clouds that would have smothered its chance to fly.

28.   But warming through thick clouds can be nullified on bridges and underpasses.

29.   Darkness falls early because of the thick clouds, and the team looks glum.

30.   Dozens of Vietnamese were also hurt in battles in which the camp was blanketed by thick clouds of tear gas.