Luo'er estimated that after sending Xilia away, it took them about a week to reach the North Lead Corridor; indeed, it was a challenging journey.
Once they arrived at the North Lead Corridor, he immediately fitted the mules and horses with anti-slip horseshoe nails, enabling them to move directly over the frozen surface of the Ebia River. This way, even though there was no shelter and the chilly winds were even more cutting, their speed could be significantly increased.
Because there was little snow accumulation on the ice, they didn't have to trudge through thick snow, and although the bitter cold winds were uncomfortable, their speed was not reduced.
Leaving the North Lead Corridor as soon as possible was Luo'er's sole goal at the moment. It was cold in the Snow Domain as well, but not as constantly windy as the North Lead Corridor.