Visibility was thin and temperatures were below freezing last Saturday at the Snow Farm. Opaque white clouds of fog swept over the landscape near Wanaka, New Zealand, showcasing a skyline that seemed to play on the country’s largest historical farm industry: sheep. If bluebird skies and sun had greeted competitors in previous years, racers in the 2017 Merino Muster experienced temperatures around -5 degree Celsius (23 Fahrenheit) and a four-meter radius of visible track, then...