How do you think the man knows about these "traps" and how does the fact that he has this knowledge tell you more about him?

From the text, we can infer that the man is not completely inexperienced. He understands and observes certain pitfalls along the way, but we can also infer that he has never made this type of journey alone...... because of this, there won't be anyone to help him if he makes a mistake.

Empty as the man's mind was of thoughts, he was keenly observant, and he noticed the changes in the creek, the curves and bends and timber-jams, and always he sharply noted where he placed his feet. Once, coming around a bend, he shied abruptly, like a startled horse, curved away from the place where he had been walking, and retreated several paces back along the trail. The creek he knew was frozen clear to the bottom, -- no creek could contain water in that arctic winter, -- but he knew also that there were springs that bubbled out from the hillsides and ran along under the snow and on top the ice of the creek. He knew that the coldest snaps never froze these springs, and he knew likewise their danger. They were traps.