Remember the wind that scatters the dry chaff,
sweeping it over the sacred threshing floor,
the men winnowing hard and blond Demeter culling
grain from dry husk in the rough and gusting wind
and under it all the heaps of chaff are piling white…
so white the Achaeans turned beneath the dust storm now,
pelting across their faces, kicked up by horses’ hoofs
to the clear bronze sky – the battle joined again.

– Homer

The Iliad, Book 5, lines 574-581. On the battlefield the Achaean troops are completely covered by a dust storm kicked up by their horses’s hoofs. An epic simile describes it as being like the dry chaff scattered by the wind when the grain is being seperated from the husks after harvest.