EF3 tornado in St. Charles County, Missouri

A tornado touched down about four miles southwest of Weldon Spring in St. Charles County, Missouri. It downed trees, blew over empty tractor trailers, and caused minor damage to construction equipment. It moved east-northeast into Weldon Spring Heights and the Missouri Research Park (on the south side of Weldon Spring) causing roof, window, and solar panel damage to a few structures as well as downing more trees before crossing Interstate 64. The tornado passed within one half of a mile of the National Weather Service Weather Forecast Office which is located in the Missouri Research Park. The tornado continued moving east-northeast through densely populated residential areas of southern St. Charles County, south of Highway 94. Roofing was torn off of Bryan Middle School and blown 100 yards, many houses suffered varying degrees of roof (from minor damage to removal of entire roof), wall (from minor damage to total collapse), and overall structural damage, and thousands of trees were damaged. The most intense damage, rated EF3, occurred on Haversham Drive where only the interior walls were left standing of three homes. The tornado began to move a bit more easterly, widening to nearly 1000 yards (or a half-mile), causing damage in residential areas and the St. Charles Family Arena before crossing the Missouri River into St. Louis County just south of Interstate 70.

The tornado caused damage to 765 homes in St. Charles County. Seven hundred twenty-three homes suffered minor damage, 34 homes suffered major damage, and 8 homes were destroyed. Three hundred forty-eight businesses sustained minor damage, while 25 businesses had major damage. Cleanup costs alone for St. Charles County was 2.4 million dollars, with approximately 50,000 tons of tree and limb debris removed. There were 8 minor injuries due to the tornado.

The path length of the tornado in St. Charles County was 14.8 miles with a max path width of 950 yards. The damage for this segment was estimated to be EF3 with max wind speeds of 150 MPH. Overall, the entire tornado path length was 31.8 miles with a max path width of 1 mile and a maximum damage rating of EF3.

Storms developed along an outflow boundary that was laid out along the I-70 corridor. The storms produced wind damage, large hail as well as 9 tornadoes. Two of the tornadoes were rated EF3 as they moved through the St. Louis metro area. Also, heavy rain fell causing flash flooding in some locations, which persisted into the early morning hours of June 1st.