Enemy Ambush
Berengar and his forces had arrived in the Viscounty of Schwaz after a few days worth of marching. Obviously, they had made camp throughout the nights. Berengar was trying to lose as few forces as possible to attrition; as such, he had kept his forces far from exhaustion and well-fed, hydrated, and equipped to combat the effects of the cold.
To him, every one of his soldiers was a precious member of his society; those lost were not easily replaced without his land suffering from it. War was necessary for expansion, but he did not want to fight a war without regard to his soldiers' lives. As such, they marched at a safe pace.