However Slesse is most famous for the Northeast Buttress, first climbed on August 28, 1963 by Fred Beckey, Steve Marts, and Eric Bjornstad.

In July 1966 Hans Baer and Jack Bryan did the second ascent of this route, with one bivouac and a straight line exit at the top of the buttress.

On December 9, 1956, Trans-Canada Air Lines Flight 810, a North Star airplane crashed on the upper slopes of the mountain, killing all 62 people aboard.

Prominent among the dead were team members of the Winnipeg Blue Bombers and Saskatchewan Roughriders, on their way home from the annual East-West All-Star Game in Vancouver.

In the 1990s the provincial government, under pressure from the Families of Slesse organization, finally passed legislation to enshrine protection of the site, which was under threat from clearcut logging at the time, and markers have been placed on trails leading into the site requesting it be respected by hikers and others accessing it.