Study shows storms are becoming more unpredictable in recent decades Research finds storms are becoming more unpredictable In addition, the research finds that droughts are now longer in duration. FOX 10's Stephanie Olmo reports. PHOENIX - In a recent study, researchers found that droughts are lasting longer and storms are more unpredictable in the last five decades. Researchers went through 50 years of weather data, and they discovered that the bigger changes took place in the desert Southwest. "What we were really trying to accomplish was looking at the day-to-day variations in rainfall across the Western United States. We were trying to take a hard look at the timing of that rainfall, how often the ground gets wet," said Dr. Joel Biederman, a research hydrologist with the United States Department of Agriculture's Southwest Watershed Research Center in Tucson.