The 25 Deadliest U.S. Tornadoes. While these spinny winds are not unique to our country, they are very much a part of the American experience. Des Moines sits at the centre of Iowa, and sees more tornadoes than other parts of the state. Daily Kansas tornado frequency 1950-2009 (above-left). The 1900 Westchester County tornado was an intense, but short-lived tornado that caused significant damage near the city of New Rochelle, New York. Major tornado disasters during the spring and summer of 1860 resurfaced previous concerns about tornadoes, and by 1862 the Smithsonian distributed circulars alerting people to their dangers. The tornado spawned from the other supercell touched down in St. Louis, Missouri, then one of the largest and most influential cities in the country.It was one of at least 18 tornadoes to occur on that day, and it quickly became the third-deadliest as well as the costliest tornado in United States history. As the graph indicates, mid to late April through mid June historically has the highest tornado frequency, with the peak occurring around May 22 nd-23 rd with over 160 tornadoes occurring over that two day period since 1950. A tornado warning was last issued in the city in October, even though tornado season is usually at its worst in late spring. Death counts for events in the 1800s and early 1900s should be treated as estimates, since recordkeeping of tornado deaths was erratic back then. Two of the most powerful storms in years hit in 2018, at Pella and Marshalltown, towns not far outside Des Moines. It wasn’t until the 1800s that advances in the understanding of tornadoes began, and some of … Tornado fascination and observation is nothing new. High winds fanned the flames into firestorms, tornado-like columns of fire that were able to leap natural firebreaks and even large bodies of water. Tornadoes have been part of the historical record for a very long time. As soon as the mid-1800s, the government began collecting data on tornadoes. Storm Prediction Center. During the afternoon of Tuesday, August 7, 1900, a strong tornado estimated at 40 ft (12 m) wide, struck the city of New Rochelle, New York along a 4 miles (6.4 km) path. Synopsis. NOTE: Having happened before the era of comprehensive damage surveys, some of these events may have been composed of multiple tornadoes along a damage path. For much of the mid-1800s, the Smithsonian Institution in Washington, D.C. was the center of weather observation for the United States. Notice the sharp drop-off by mid to late June.