National Geographic : 1986 Sep
WILL SITEGER(UVERLEAFANDABOVE) 4 Off and runningat minus 68°F, the expedition departs from northern Ellesmere Island on March 8 (overleaf). Beyond one of the five sleds looms a ghostly vapor trail created in the turbulent wake of the dogs' perspiration and breath, trapped by an inversion between cold air from the mountains and the even colder ground. Improvising a ferry, the team uses a small ice floe to cross a lead of open water (above) north of latitude 87° amid warming weather. Peary sometimes crossed leads by using the same technique (right). He dreaded such sudden breaks as a "nightmare.... the unknown quantity of the polar equation."