Unseasonably rainy weather grounded the German Air Force as Army Group South reached the wide barrier of the Dnepr River. The invaders now had to reckon not only with the river itself and the Soviet troops waiting on the other ride, but the river monitors steaming up and down it with impunity under the gray skies. But a little rain won't stop a helicopter

The Soviets had built their river monitors (or in the case of these formerly Polish monitors, re-fitted them) with the expectation that they would face an unfriendly air environment, even if they had not anticipated the German deployment of helicopters - machines well-known in the pre-war Soviet Union. The river monitors had the ability to shoot back at the helicopters, but lacked their mobility and despite heavy losses among the flying machines, the river would be cleared of enemy warships to allow an assault crossing.