A particularly intense tornado hits Sherman, Texas, on this day in 1896, and kills 73 people. It is estimated that the tornado was a rare F5 tornado, in which winds exceeded 260 miles per hour. Storms of that strength happen, on average, less than once a year.
The strength of tornadoes is measured on the Fujita Scale, named after University of Chicago physicist Tetsuya Theodore Fujita. He was the first scientist to devote extensive study to tornadoes and how they operate. He discovered that the average tornado is 150 feet wide, travels one mile moving 40 mph in a northeasterly direction and tends to pick up strength the longer it lasts. Fujita found that only 30 percent of twisters reach winds above 112 miles per hour. The strongest tornadoes--ones that cause complete destruction on the ground, even to steel-reinforced structures--are designated as F5 on the scale designed by Fujita and only occur in North America. There were 94 recorded F5 tornadoes in the 20th century.
The tornado that hit Sherman on May 15 is considered an F5 because of the complete and utter destruction it caused. Most of the homes it demolished were totally razed--there was hardly a trace left of them when the twister passed. The Houston Street Bridge in Sherman was smashed and brought down by the tornado. The trunk lid from a car in Sherman ended up 35 miles away. Sixty people, including whole families, perished in the town that day.