Answer:
Poor weather conditions
Step-by-step explanation:
When the Wehrmacht, the Nazi army, invaded Russia under the Barbarossa Operation in 1941, they had to move their troops a long way through large territories until the tough Russian winter arrived. The troops almost couldn't move because of the rasputitsa, a fusion of mud and snow that impeded the movement of transport and men. This extreme weather conditions stopped the advance of the Blitzkrieg and, finally, was a decisive cause of the retreat of the Nazi army in Russia.