An expert talks about the unpredictability of Arizona’s monsoon season, and explains why this year’s monsoon season is wetter than last year’s.

Randy Cerveny, professor of Geological Science at Arizona State University, says the wetness of a monsoon season depends on how early heating over the desert occurs. If there isn’t enough heating you don’t get the proper wind shift. Cerveny says Arizona got lucky this year and managed to draw a lot of moisture in. He says that another factor is terrain.

Cerveny says the Phoenix area usually needs to hit 105 degrees to create the right environment for a monsoon.

Cerveny also addressed the nationwide drought and says that it’s common to have periodic droughts. He says that the current drought is comparable to one in the 1950s, and if it doesn’t break there’s a possibility it could reach dust bowl proportions.