More or less if you have already answered the question the simplest way to think about it is a combination of the wind and the currents in the ocean what happens some places is because when the water hits the land there isn't enough of a condensation layer I guess is the correct term Normally what happens when moisture rises it gets enough Dusty water actually needs particles to condense on before I'll come down in the rain and there is enough particles in the Air Force to condense on and so it doesn't rain that's why I have to happen is some places so what happened in United States back between series they had a major change in the water system or another place didn't get rain for or very low rain for a number of years

And this is actually a concern for a lot of people because there's a lot of evidence that some deserts even just 500 years ago were actually tropical rainforest and what assistance change and now they're deserts