To form, these storms require three basic ingredients: Moisture, unstable air and lift. Moisture in the air typically comes from the oceans—and areas near warm ocean currents evaporate lots of moisture into the air. Moisture in the air is also responsible for making clouds.
People are naturally going to live near clean water sources, that way it's easier to survive, so people are more likely to live near or in an oasis than in a hot dry area like a desert.
