photo #6608581

Storm Cloud Week: SundayThe defining characteristic of supercell storms, like this one spotted by Ryan Weller south of Miltona, Minnesota, US and shared by Mary Kessle (Member 51,523), is the large rotating central part known as a mesocyclone. This marks the region where warm, moist air is being sucked in to form a rotating updraft that feeds the massive storm. Inflows and outflows, updrafts and downdrafts, dry regions and precipitation zones all coordinate as a perfect storm structure in a supercell. This ensures it is long lasting and likely to spawn tornadoes, hail, and torrential downpours.According to the US National Weather Service, in an average year, the country experiences over 10,000 severe thunderstorms, 5,000 floods, and more than 1,000 tornadoes. In the 1970s, the Service began a volunteer program for the reporting of timely and accurate severe weather information. Today, Skywarn has between 350,000 and 400,000 trained spotters who are alerted whenever severe weather threatens. Mary tells us that on July 18, 1970, a tornado swept through Miltona, leaving a three-mile-long path of destruction through the middle of town. To commemorate the town’s comeback, Miltona has held an annual Tornado Days parade in mid-July ever since.Supercell photo by Ryan Weller, shared by Mary Kessle (Member 51,523) with his permission.