Mount Logan

A 5,959-metre peak in the Saint Elias range of the Yukon Territory, Canada — the second-highest mountain in North America after Denali, and the largest mountain on Earth measured by base circumference. Mount Logan's massif covers an area larger than the entire Mont Blanc range. The summit ridge is over twenty kilometres long and carries multiple subsidiary peaks, eleven of which exceed 5,000 metres on their own. The mountain was named in 1890 for Sir William Edmond Logan, the Scottish-born Canadian geologist who founded the Geological Survey of Canada.

The first ascent came in 1925, by an international expedition organized by the Alpine Club of Canada and led by Albert MacCarthy. The team — six climbers, six weeks of approach, eighty days from base camp to summit — represents one of the most ambitious mountaineering efforts of the interwar period. The standard route they pioneered, the King Trench, follows a long glaciated valley to a high plateau before the final summit ridge. The route has remained essentially unchanged.

What separates Logan from peaks of comparable altitude in other ranges is the cold. The mountain holds the lowest sustained recorded temperatures of any mountain on Earth. Winter temperatures at the summit have been documented below minus 70 Celsius, and the wind chill on the upper plateau in storm conditions has been calculated below minus 100. The climbing season is brief — late April through mid-June — and even within the season, weather windows are short. Most expeditions spend two to three weeks at high camps waiting for opportunities to reach the summit.

The fatality rate has been moderate. Most accidents have involved exposure on the upper plateau during weather changes, or crevasse falls on the long glaciated approach. Logan does not draw the volume of attempts that Denali receives, partly because of the longer approach and partly because the peak is logistically demanding without offering Denali's iconic profile. For climbers building toward extreme-cold expeditions — Antarctica, Greenland, winter Himalaya — Logan has functioned as a primary training ground.