<P> Research focused on four individual days that accumulated more than 5.9 inches (15 cm) of hail in 30 minutes on the Colorado front range has shown that these events share similar patterns in observed synoptic weather, radar, and lightning characteristics, suggesting the possibility of predicting these events prior to their occurrence . A fundamental problem in continuing research in this area is that, unlike hail diameter, hail depth is not commonly reported . The lack of data leaves researchers and forecasters in the dark when trying to verify operational methods . A cooperative effort between the University of Colorado and the National Weather Service is in progress . The joint project's goal is to enlist the help of the general public to develop a database of hail accumulation depths . </P> <P> During the Middle Ages, people in Europe used to ring church bells and fire cannons to try to prevent hail, and the subsequent damage to crops . Updated versions of this approach are available as modern hail cannons . Cloud seeding after World War II was done to eliminate the hail threat, particularly across the Soviet Union--where it was claimed a 70 to 98 percent reduction in crop damage from hail storms was achieved by deploying silver iodide in clouds using rockets and artillery shells . Hail suppression programs have been undertaken by 15 countries between 1965 and 2005 . </P>

Which type of front was producing the weather in nebraska when this image was taken