Experts say it's been an unusually mild year in Tornado Alley. The region generally extends from Texas and Oklahoma to Kansas, Nebraska, Iowa and Minnesota.
Nationwide, there were 826 tornadoes this year through June 30, compared with an average of 934 for the same period during the previous three years. That's according to the National Severe Storms Laboratory in Norman, Okla.
During a remarkable 17-day lull from mid-May through early June, there were no tornado watches issued anywhere in the United States. And that is typically the height of the season in Tornado Alley.
Southern states see most of the winter tornadoes. But in the spring and early summer, the focus shifts to the nation's midsection. The area is particularly fertile for tornadoes then because of hot, dry air from the west colliding with moist air that flows up from the Gulf of Mexico.