“Weather and visibility are such that it is not safe for aircraft to arrive or depart at this time,” Denver International Airport said on Twitter. The storm was forecast to track east, possibly bringing heavy snow along a swatch of the upper Midwest.The airport is one of the busiest for Southwest Airlines. March is the snowiest month in Denver. Wintry weather was also creating disruptions for fliers at Minneapolis/St. Paul. Denver International Airport is the largest airport in the United States by total land area. In 2015, when it was serving 187 destinations throughout North America, Latin America, Europe and Asia, it was the 18th-busiest airport in the world and the 6th busiest in the United States by passenger traffic with over 54 million passengers. DIA is the only airport in the United States to have implemented an ISO 14001-certified environmental management system covering the entire airport.