Face to face with the jet stream
Among its myriad of influences, World War II took aviation to new heights. Fighter planes regularly soared above 8km/5 miles.There they found a strange, strong wind that blew at unheard-of speeds. One Nazi spy-plane reported 170-knot winds (310kph/195mph) before it crashed in the eastern Mediterranean. In November 1944, two US squadrons approaching Tokyo from the southwest were suddenly swept forward by unexpected tailwinds that made bombing impractical. Meanwhile, Japan was putting the jet stream to work by launching some 10,000 “balloon bombs”. A few hundred of these small, hydrogen-inflated craft traversed the Pacific and made it to US shores, although their arrival was hushed up by wartime censors. Most of them landed in the Pacific Northwest, where frequent winter rains quenched the risk of explosion or fire – although not completely. Seven members of an Oregon family came upon a balloon bomb while picnicking in May 1945. Six of them were killed – they were the only civilian casualties of World War II in the 48 contiguous US states. By war's end, the jet stream had made a name for itself, but it was years before upper-air measurements brought its ever-changing structure to light.