Meteorologists call this area a WER, which stands for "weak echo region". Strong updrafts create a rain-free area in supercell thunderstorms. The air bubbles are "frozen" in place, leaving cloudy ice. With dry growth, the air temperature is well below freezing, and the water droplet immediately freezes as it collides with the nucleus. Since the process is slow, air bubbles can escape, resulting in a layer of clear ice. Instead, liquid water spreads across tumbling hailstones and slowly freezes. Upon colliding with a supercooled drop, the water does not immediately freeze around the nucleus. In wet growth, the hailstone nucleus (a tiny piece of ice) is in a region where the air temperature is just below freezing, not super cold. There are two methods by which the hailstone grows, wet growth and dry growth, and which produce the "layered look" of hail. Hailstones grow by collision with supercooled water drops (Supercooled drops are liquid drops surrounded by air that is below freezing, which is a common occurrence in thunderstorms). Why? The freezing level in the Florida thunderstorms is so high, the hail often melts before reaching the ground. While Florida has the most thunderstorms, New Mexico, Colorado, and Wyoming usually have the most hail storms. One of the people killed during the March 28, 2000, tornado in Fort Worth was killed when struck by grapefruit-size hail. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people. Hail is precipitation that is formed when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere. National Centers for Environmental Prediction.Preparedness and Mitigation: Individuals (You!).Preparedness and Mitigation: Communities.The Positive and Negative Side of Lightning.
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