61.   This would diminish the dust cloud, he said, but there could still be a water plume.

62.   Using NASA satellites to track the African dust clouds, they were able to take air samples both on clear days and days with dust plumes affecting the region.

63.   He said the fragments were hidden behind dust clouds so astronomers watching their progress could only estimate their size.

64.   But as Operation Anaconda entered its seventh day, the allied forces faced dust clouds and a forecast of snow.

65.   But as Operation Anaconda entered its seventh day, the allied forces faced dust clouds, sub-zero temperature winds and a forecast of snow.

66.   The team also conducted experiments to confirm a theory that particles in space tend to attract each other and form dust clouds.

67.   Military vehicles stir up occasional dust clouds.

68.   Scientists believe the object, either a comet or an asteroid, triggered a firestorm and then a dust cloud that obscured sunlight.

69.   The crew of the shuttle Columbia conducted experiments Tuesday to confirm a theory that particles in space tend to attract each other and form dust clouds.