Roughly how much of London's story is devoted to describing the setting? What particular details make it memorable?

I would say the majority of London's story is devoted to the setting, particularly, as the Yukon was one of his own favorites places on Earth. The frigid cold..... the crackles, the man's beard frozen with tobacco juice..... the man wanting to take the dog's life in order to bury himself within its warmth..... all of these things paint a picture. We can almost feel it...... see it....... hear the crack of the tree bough as it falls over the fire. London's descriptions of the setting are unequaled..... they take us there.