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~ I I I I I I I I I I I I I ) I I I I Supercells are among the most dangerous variety of clouds to deal with both from a cloud seeding aspect as well as a crop and property damage aspect. Hail is capable of being ejected from these clouds in any direction and occasionally can endanger seeding aircraft several miles distant from it. Supercells also produce the most destructive tornadoes (on the Fujita Scale types F3 - F5), however, not all supercells produce tornadoes; some estimates indicate about 20%-25% of all supercells may produce a tornado. During the WKWMP 27 years of seeding supercells to prevent hail we've also had serendipity: We've found out seeding to reduce hail in these storms is likely to be producing the effect of inadvertent tornado-mitigation. The expectation that cloud seeding can accomplish tornado mitigation is not new and earlier has been theorized by others. The WKWMP is the only cloud seeding group in the USA that has been uniquely able to test the theory over a protracted period of time. We are the only cloud seeding program in the United States that seeds all severe storms, We often prefer to seed storms that have a funnel cloud or a tornado in progress because they are usually the most intense storms; devastating hail almost always accompanies them, They usually travel great distances across our target area and are most responsible for causing a disproportionately large percentage ofthe total seasonal crop-hail damage on a given day. Conceptually, it's not completely clear why, or how, a massive water-to-ice conversion process that releases vast amounts oflatent heat inside a supercell may be able to mitigate a tornado. Even cloud physicists who are expert in tornado development don't totally understand why tornadoes form, although they are homing in on this knowledge more all the time, albeit, little by little. However, the relevance of this seeding effect is useful to the general community within the target area we attempt to protect; we have come to expect that the proper seeding of supercells will mitigate tornado severity in tornado-bearing storms. But, this bears repeating: If inadvertent tornado mitigation really is occurring, adequate amounts of seeding agents must be well-dispersed within the new growth clouds which feed into the primary updraft(s) of the complex supercell storm system, Storms which are abandoned, or not well-seeded, often seem to be prone to producing a tornado in short order, because the cloud is returning to its natural, or near-natural, state. This can happen swiftly, too, within perhaps as few as 20-30 minutes (estimated) after seeding ends, The cloud system known as the squall line is an organized line of cumulonimbus clouds many miles in length, Important updraft areas are found along its advancing cloud edges. Updrafts important to the precipitation and hail processes are seldom found along the trailing edges of these lines except at its tail-end, or at significant breaks within the line, Squall lines can be extensive, crossing a few counties within a state, or even crossing several states; frequently squall lines are associated with surface troughing ahead of frontal passages. Updrafts can easily exceed 2,000 - 4,000 feet per minute and produce "scud" clouds visible nearly to the ground. Ahead of the squall line, updraft areas are usually smooth. Convective Scale Interaction is a term given to a very important process set into motion when a collapsing storm produces precipitation, As the downdraft air, associated with the falling 10