When Hell froze over--they called it Stalingrad.
http://www.secondworldwarhistory.com/battle-of-stalingrad.asp
The severe cold slowed the German advance down in many ways, the Germans were not used to fighting in the cold weather so it affected their combat performance. Also, their supplies were not designed for this kind of weather--their coats and boots where too thin. The last but biggest reason is that their vehicles were not designed for Russia's extreme winter, and as a result, they broke down due to their fuel tanks freezing and the tracks getting stuck in the snow. This meant that the infantry could not be supported by vehicles, so equipment could not arrive to troops on time. As the winter turned to spring , snow melted and presented a new problem--mud--which bogged down infantry and vehicles.
The severe cold slowed the German advance down in many ways, the Germans were not used to fighting in the cold weather so it affected their combat performance. Also, their supplies were not designed for this kind of weather--their coats and boots where too thin. The last but biggest reason is that their vehicles were not designed for Russia's extreme winter, and as a result, they broke down due to their fuel tanks freezing and the tracks getting stuck in the snow. This meant that the infantry could not be supported by vehicles, so equipment could not arrive to troops on time. As the winter turned to spring , snow melted and presented a new problem--mud--which bogged down infantry and vehicles.
