The widespread devastation and personal tragedies resulting from hurricanes, should make many ask: What causes hurricanes? The video below provides the explanation, but it goes by fast. It deserves pausing and further emphasis on key points, all of which are covered in various BFSU lessons.
Air over equatorial west Africa and the eastern Atlantic just northward of the equator is heated by the summer sun. (Lesson D-9)
Warm air rises. Rising air results in low pressure below. Surrounding air moves in fill the low pressure space, but this in-moving air moves in a spiral due to the Coriolis effect. (Lesson D-16)
The low pressure over the Atlantic’s warmed water increases the rate of evaporation–entry of water vapor into the rising air column. Lesson A-13 and A-17.
The warm moist air cools as rises and water vapor begins to condense leading to clouds and rain.
But condensation also releases heat energy. (Lesson A-8) This heating compounds the rise of the central column of air, the low pressure under it, and the evaporation of water–water vapor entering the system. This positive feedback loop results in the hurricane gaining both size and strength as it crosses the Atlantic pushed by the trade-winds. (Lesson D-16)
This also explains why the hurricane dies as it gets over land; it no longer has the input of water vapor that keeps it going.
We should also see in this why hurricanes are predicted to increase in both size and intensity in the years ahead. Ocean temperatures are increasing as a result toe global warming. Hence they are more vulnerable to evaporation and triggering the heat engine that spawns hurricanes.
Here is the video: https://www.youtube.com/watch?v=HJydFJORWf4