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<br />~ <br />'I <br />I <br />I <br />I <br />, <br />I <br />! <br />, <br />I <br />I <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />The sizes and concentrations of all nuclei present in the atmosphere as well as their <br />chemical and electrical properties all combine in important ways to determine how efficiently a <br />cloud system can produce precipitation, Although there is a massive amount of water vapor in <br />the atmosphere at any time, precipitation won't occur if certain conditions required for the <br />formation of precipitation are absent. <br /> <br />Two cloud types produce all precipitation: "warm clouds" and "cold clouds." A "warm" <br />cloud is one in which nowhere in its volume is its temperature below freezing---able to produce <br />ice crystals. The convective warm cloud is characterized most often by relatively slow growth, <br />Warm cloud water droplets eventually may grow to a sufficient size and weight to fall out of the <br />cloud if given enough time. Falling cloud droplets grow larger by scavenging other cloud droplets <br />along their downward paths, Although this type of cloud appears in Western Kansas, it's not the <br />dominant type of cloud producing precipitation here. Interestingly, large-sized rain drops can be <br />important embryo sources in the production of hail when carried aloft rapidly by updrafts into <br />sub-freezing cold clouds where eventually they freeze and grow quickly into large hail. While <br />seeding, pilots often find rain falling into below-cloud base updraft areas, <br /> <br />However, most important to Western Kansas is the "cold" cloud, Cold clouds tend to be <br />much taller and have more volume than warm clouds, so there is a greater amount of moisture <br />available to the precipitation process developing within the cloud. Cold clouds have a portion of <br />their volume that has risen high enough to have passed into below-freezing atmospheric <br />temperatures. When such clouds fonn, the interaction between the supercooled water drops and <br />ice crystals within the cloud initiates the process responsible for producing most significant <br />precipitation in Western Kansas and does so in a relatively short time span compared to wann <br />clouds. <br /> <br />The widely-accepted seeding hypothesis under which the WKWMP hail suppression <br />-operates is based upon "beneficial competition." Most, if not all, credible long-tenn hail <br />suppression programs assume beneficial competition is needed to solve the hail problem, As <br />mentioned earlier, hailstones grow to large sizes in thunderstonns due to the lack of sufficient <br />numbers of IN particles within the cold cloud while it is growing, This natural insufficiency of IN <br />particles allows relatively abundant supercooled water droplets to collect upon the relatively few <br />numbers of ice crystals causing hail to grow to large sizes. Too often those ice particles grow into <br />hailstones so large they can't melt before reaching the earth's surface. By vastly increasing the <br />concentration of ice crystals within these ice crystal-deficient clouds, competition for available <br />cloud water increases to the point that hailstones are prevented from attaining sizes large enough <br />to damage crops and property, Hail growth and movement within storms, especially very severe <br />ones, can be very complex, In very strong storms hail may be cast miles distant from the storm <br />itself Hail damage is determined by many factors: the type of crop and the stage of growth the <br />crop was in, the hail size affecting the crop and whether or not it was wind-driven are all <br />important considerations, Those same general factors also apply to any property damaged by hail <br />(i,e. resilience to hail, size of hail, etc.). <br /> <br />5 <br />