Playas are the dry, level beds of ancient 
        lakes which are found in desert country throughout the southern 
        Southwest. Normally dry, playas occasionally fill with water, sometimes 
        no more than a few inches deep over  
        many square miles, after a heavy summer rain or during spring snowmelt. 
        These shallow lakes usually last no more than a few days or weeks, 
        evaporating to leave behind a large expanse of mudflats drying in the 
        sun. Playas were named by Spanish explorers for their resemblance to 
        beaches. 
 
          
          
            
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               The playa at right was 
              photographed at the Racetrack in Death Valley National Park.
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          Playas are 
          characteristic of desert areas and are maintained by climates that are 
          drier than they are wet, where the combination of relentless sun, wind 
          and aridity can evaporate more water from the land than falls in a 
          year. Most of the Southwest's playas formed thousands of years ago 
          during the Pleistocene period when the climate in the Southwest was 
          cooler and wetter. Precipitation eroded mountains and streams carried 
          sediments to low level basins between mountain ranges which filled 
          lakes with fine sand and silt. As the climate warmed and dried 
          10,000-12,000 years ago, the streams dried up and the lakes 
          evaporated, leaving their flat beds to dry and harden. 
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
        
         
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