The man is the main character and he is in the snow trying to get to the boys with his dog. It is 75 degress below 0 and the cold doesn't bother him and that he was use to it. "the absences of sun from the sky, the tremendous cold, and the strangeness of it all-made no impression on the man"
The man is trying to get to the boys at their camp, but it is 75 degrees below zero and it was too cold to be going there by himself and also too dangerous due to risks of breaking and falling into the water "it was colder than sixty below , than seventy below. It was seventy-five below zero".
As the man was walking with his dog the man falls through the ice and wets his feet with the water going up through his knees