A dust storm struck north-central Texas on April 6, 2006. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite took this picture the same day. In this image, a tan plume of dust, near the bottom of the image, swirls in a counter-clockwise direction toward the northeast. North of that storm, in the Texas panhandle, are two smaller plumes of dust. These dust plumes appear to originate from burn scars left by fires in March 2006. Fires -- and dust storms-- in this region have been exacerbated by drought and low humidity, which have created a large stockpile of dry vegetation (brush, grasses, and trees) that, once ignited, are spread by moderately strong winds. This condition has caused the more than 10,000 wildfires that have burned at least 1.6 million hectares (4 million acres) since late December 2005. In addition to the direct effects of burning, smoke – as well as the dust that might follow- from the fires is also a major health concern, causing irritation to the lining of the lungs. In addition, the poor visibility caused by dust is a hazard to navigation.