Because they feed on heat, hurricanes need water that is at least 80°F from the surface down to a depth of about 150 feet. The atmosphere above a developing storm must be substantially cooler than the surface, allowing the system to develop towering thunderclouds. The midlevel layers of the atmosphere must be saturated with water vapor, adding to the fuel that powers the storm. As noted earlier, hurricanes can’t form at the equator, so a developing storm has to be at least 500 miles away from zero latitude to get going, and there must be at least some low-level spin in the atmosphere to get it
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