"It was a certain weather pattern that spared Fujita from that bombing, allowing him to pursue his atmospheric discoveries.
Fujita was living in Kokura, Japan during World War II, which was the primary target for the “Fat Man” atomic bomb. But on the morning of August 9, 1945, the city was obscured by clouds and smoke, so the bomb was dropped on the secondary target, Nagasaki."
Wikipedia: “Although he is best known for creating the Fujita scale of tornado intensity and damage, he also discovered downbursts and microbursts and was an instrumental figure in advancing modern understanding of many severe weather phenomena and how they affect people and communities, especially through his work exploring the relationship between wind speed and damage.”