National Weather Service maps Marshalltown Tornado
The National Weather Service analyzed data from the tornado that tore through Marshalltown on July 19. Here is what they found. The information is directly from the National Weather Service Des Moines administration.
• Time — 4:25 p.m. to 4:48 p.m.
• EF rating — EF-3
• Peak winds estimate — 144 mph
• Path length — 8.26 miles
• Max width — 900 yards
• Injuries and deaths — 0/0
The tornado developed northwest of Marshalltown near the little hamlet of Marietta, according to the NWS. The tornado traveled southeast on the western side of the Iowa River producing extensive crop and tree damage. The tornado strengthened quickly and took on a wedge appearance as it entered northwest Marshalltown. The tornado tracked more easterly as it entered town producing widespread EF-1 and EF-2 damage. The tornado went straight through the business district of downtown with EF-2 and EF-3 damage to many structures, including the county courthouse which lost the spire off the clock tower. The tornado continued east through housing areas before encountering the Lennox plant on the east side of town, producing EF-3 damage once again. The tornado began to weaken rapidly after this point and dissipated east of the power plant.