The extent of the damage to crops is depicted in this vegetation anomaly map based on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
The map contrasts plant health in the central United States between June 25 and July 10, 2012, against the average conditions between 2002 and 2012. Brown areas show where plant growth was less vigorous than normal; cream colors depict normal levels of growth; and green indicates abnormally lush vegetation. Data was not available in the gray areas due to snow or cloud cover. The image is based on the Normalized Difference Vegetation Index (NDVI), a measure of how much plant leaves absorb visible light and reflect infrared light. Drought-stressed vegetation reflects more visible light and less infrared than healthy vegetation