In the book Night, how do the prisoners manage to go on to run for miles, in deep snow?

The prisoners had prior information about their evacuation from Buna. It was winter, and the Russian army was advancing towards the camp. In the morning, on the day of their evacuation, the prisoners prepared for the journey. They wore layers upon layers of prison clothes to keep warm.

IN THE MORNING, the camp did not look the same. The prisonersshowed up in all kinds of strange garb; it looked like amasquerade. We each...

The prisoners had prior information about their evacuation from Buna. It was winter, and the Russian army was advancing towards the camp. In the morning, on the day of their evacuation, the prisoners prepared for the journey. They wore layers upon layers of prison clothes to keep warm.

IN THE MORNING, the camp did not look the same. The prisoners
showed up in all kinds of strange garb; it looked like a
masquerade. We each had put on several garments, one over the
other, to better protect ourselves from the cold.

They also stocked up on their ration of food. At nightfall, the prisoners were asked t fall into ranks, and the journey out of Buna commenced. Fear of death significantly motivated the prisoners to move faster in the deep snow. The SS had orders to shoot anyone who slowed down, and they did not hesitate to carry out the orders. The journey started with the prisoners walking, but on orders of the SS, the prisoners were forced to increase their pace.

In summary, it was mostly their will to survive that motivated them to proceed with the journey under harsh conditions.