In Nevada, Fires Follow Rain
When you think of a desert state like Nevada, wildfires might not immediately come to mind. The low brush and shrubs in Nevada can fuel fires, however, and summers following above average winter rains often see more fires than usual. This is because the rain promotes plant growth, so there is more fuel available to spread a big fire.
Images from satellites can help scientists identify where wildfires are burning. They can also measure the "greenness" of the land, which represents how abundant plant growth is on the ground. Images from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) capture this greenness, and every week the Wildland Fire Assessment System analyzes the conditions. This constant measurement provides a useful indicator of what the wildfire risk is from region to region. When the image is brown or red, it means the ecosystem is very dry. On the other hand, green on the land means there is more lush vegetation and plant growth.
More fires are expected in Nevada when MODIS images are greener than average during the fire season. In the above graphic, the greenness images were taken during the weeks of June 24, 2003 and June 28, 2005; these weeks occurred early in the fire season, when many wildfires were just beginning.