There are several factors that contribute to make the central United States uniquely situated for getting supercell thunderstorms and large tornadoes, but the main reason is the flat terrain , that is , option b.
The central United States is known as "Tornado Alley" because it is uniquely situated for getting supercell thunderstorms and large tornadoes. The lack of trees in this region allows for unobstructed air flow, which helps to create the necessary conditions for supercells to form.
Additionally, the central US is located in an area where Arctic air can directly meet tropical air without any geographic impediment. This collision of air masses creates a strong contrast in temperature and humidity, which can trigger severe weather events. Finally, cold fronts that move across the region can also contribute to the formation of supercells and tornadoes. Overall, the combination of flat terrain, favorable atmospheric conditions, and geographic location makes the central United States a hotspot for supercell thunderstorms and large tornadoes.
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