Trailing dust devils

Trailing dust devils

Whirlwinds create dark paths by sucking sand grains clean

By Sid Perkins, 07:04 AM July 28, 2010

The ephemeral dark trails left in desert sand by dust devils are produced when the whirlwinds blow tiny particles of lighter-colored silt and dust off larger sand grains, a new study shows. Even removing a layer of dust and silt only a few micrometers thick can produce a dark trail visible with satellites, recent field studies suggest.

Dust devil trails have been spotted on space-based images of both Mars and Earth (SN: 5/8/04, p. 302). Oddly, scientists are much more familiar with the phen...

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