Use of NDVI Satellite Data to Identify and Document Destructive Hail Swaths
This study takes the method used by Gallo et al. 2012 and applies it to an event in northeast Nebraska on 18 August 2011. A supercell moved from Yankton, South Dakota southeastward across Dixon County Nebraska and into west central Iowa. Hail up to 10.1 cm (4 in) in diameter was accompanied by winds over 30 m s-1 producing widespread agricultural damage as well as damage to homes. On 25 August 2011, a damage survey was done over Dixon County, Nebraska and photographs were taken to document the damage to agriculture. This was followed by a phone survey within one township of Dixon County in which estimated hail size and wind speeds were recorded. It was found that the variation in NDVI differences along the storm path generally corresponded to observed variations in damage to crops. The NDVI difference were also compared to different radar signatures and algorithms, such as composite reflectivity above predefined isothermal surfaces and lowest-tilt radial velocity, to determine if these products could serve as a predictor to aid forecasters in accurately warning the public of a destructive hailstorm.