Answer: August Derecho
Explanation:
The most costly thunderstorm in the US history is the August Derecho thunderstorm. It happened on the 10th of August 2020 with Iowa being the most hit followed by Illinois, Ohio, Minnesota and Indiana.
The thunderstorm was a rare wind storm that was one of the most costly thunderstorms recorded in the US history that generated winds of up to 140mph that took out the power of more than half a moly residents, damaged their crops and homes and also killed a few people.
The thunderstorm incurred $7.5 billion and more in damages.