Several tornadoes were produced by a strongly rotating low-pressure system which passed through the Northern Plains Saturday and on across the Upper Midwest Sunday and Monday. Although later than average, fall tornadoes are not as uncommon as one might be led to think. The weather does not put up walls to separate the seasons. The shoulder seasons of fall and winter are often an uneven transition.
Although many people think of tornadoes as being almost mystical, they are really just made of wind and are caused by a particular set of circumstances which sometimes occur in thunderstorms. These circumstances are a lot more common in summer in our region, but are known to happen in other times of year. Tornado outbreaks have happened as late as early November in North Dakota and have even happened in the middle of January as far north as Iowa and Illinois.