Using Landsat to Identify Thunderstorm Damage in Agricultural Regions

During 12 and 18 August 1999, severe thunderstorms produced damaging winds and hail that caused an estimated $50 million in damage to agriculture in west-central Illinois. Landsat-7 imagery was obtained to determine the arealextent of damage and produce a crop damage dollar estimate. The normalized difference vegetation index (NDVI) was calculated for images taken “before” and “after” the severe thunderstorm events in order to examine the changes in NDVI, or vegetation vigor. A differenced image was also produced by subtracting the NDVI of the two images. Landsat-7 data was found to be useful for identifying the areal extent of severe thunderstorm damage in west-central Illinois. In comparing the detection of damage produced by high winds and hail, it was found that hail damage was considerably easier to identify. This is due to the fact that large hail typically destroys the crops while high winds blow over corn plants that can remain rooted and survive. Additionally, county estimates of dollar ...