Desert's fragile crust takes millennia to form but only moments to destroy
As they barreled across the desert toward Baghdad during the U.S.-led invasion of Iraq last March, the tanks, trucks, and armored personnel carriers churned up huge clouds of dust. Iraqi vehicles mobilized to defend against the onslaught generated their own plumes of grit. In a literal sense at least, much of the dust in Iraq has begun to settle. If history is a guide, however, the ruts the combat vehicles left behind will spew prodigious amounts of dust for years. That airborne material can cause major environmental and health problems.