Coastal forests and shrublands can be vulnerable to climate-associated disturbances such as the strong winds and storm surges associated with hurricanes. Because of its extension into the Atlantic, eastern North Carolina is especially vulnerable to such storms, having been hit by several hurricanes during the MODIS period of record (i.e., since 2000). In 2014, Hurricane Arthur struck causing relatively minor damage to forests compared to two earlier events, namely 2003's Hurricane Isabel and 2011's Hurricane Irene.
During the first week of June 2014, hail caused significant damage to corn and soybean fields in eastern Nebraska and western Iowa. By June 9th, ForWarn's all-lands product was beginning to show the losses that these storms inflicted across multiple counties despite later than average crop growth in May, and when ForWarn's next product was produced for June 17th, the losses from hail were clearly visible. These maps were made by comparing current NDVI conditions to the all-year mean value for a 24-day period maximum covering the years 2000-2013.
ForWarn's true color product is produced every 8 days at 1km resolution to provide a quality control for ForWarn's disturbance maps. Clouds and snow cover that persists for the entire 24-day MODIS collection window can create the appearance of vegetation disturbance, when it is not. In addition, these true color images show variation in vegetation greenness seasonally and among years.