An unprecedented tsunami of tornadoes hit six states over the weekend. The havoc is enormous. Tornadoers and experts call last weekend’s passage unprecedented. But how come those tornadoes were so devastating?
Tornado Alley. That is the name of the part of the United States where tornado chasers usually get their money’s worth. The strip where the heaviest tornadoes rage is formed by Oklahoma, Texas and Kansas. Southern states. The most dangerous season? The months of April and May. The fact that dozens of tornadoes have now swept through the American Midwest, even in December, is highly exceptional. Even unseen.
American weather specialists pointed this weekend to a double observation: first and foremost, the large temperature fluctuations in the country. For example, the mercury recently reached 30 degrees in the far south in Houston, while it snowed in Denver, 1,200 kilometres north. These differences lead to violent storms. In the margins of this came heavy snow showers.
The second crucial element for tornadoes is the wind shear, i.e. the wind speed that changes rapidly as the height increases. For example, differences in wind speed of 30 km/h were measured at an altitude of one kilometre. Early analyzes showed that the most giant, most devastating tornado originated in Arkansas and moved northeast into Breckenridge County, near Louisville. Good for a record of 340 kilometres.