OSLO, Norway — The modernist Holmenkollbakken ski-jumping hill lords over the otherwise bucolic Holmenkollen ski venue. It’s certainly one of the wonders of the modern nordic sport world as the steel structure arcs elegantly toward the sky. At times during the men’s 50-kilometer classic mass start on Saturday at Holmenkollen, the sun glared off the jump, giving it the appearance of a polished silver spaceship. During the women’s 30 k classic mass start on Sunday, fog descended...