Puzzling skiers, occasional brownish-yellow plumes waft over Colorado ski resorts during winter and spring. Instead of wondering, researchers led by scientists at Pacific Northwest National Laboratory decided to get to the bottom of the plumes’ source and content. Their research, now published in the Journal of Atmospheric Sciences found that the plumes hold countless dust particles carried from remote desert areas in Asia and Africa-dust from thousands of miles away travels to the western United States by high-altitude winds over the Pacific Ocean. The researchers also found that the atmospheric lifetime of the larger-sized dust particles is longer than expected. Climate models had always assumed the largest particles would fall out and not be transported such long distances.