Here's why:

* The troposphere is the lowest layer of the atmosphere. It's where weather happens, including the formation of clouds, precipitation, and storms.

* Hurricanes require warm, moist air to form. The troposphere contains the majority of the Earth's atmosphere's water vapor and experiences the most significant temperature differences that drive weather patterns.

* Hurricanes draw energy from the warm ocean surface. This warm water is found within the troposphere.

* Hurricanes' vertical structure extends into the troposphere. They typically reach heights of 10-15 kilometers, staying well within the troposphere.

While hurricanes are formed in the troposphere, they can sometimes extend into the lower portion of the stratosphere, but their primary development and energy source are within the troposphere.