A man walks behind the Olympic rings ahead of the men's snowboard cross qualification round at the 2014 Sochi Winter Olympic Games in Rosa Khutor February 17, 2014. Thick fog in the Caucasus mountains on Monday morning poses a threat to the men's snowboard cross Olympic competition, which was due to start at 1100 local time (0700GMT). Fog and drizzle shrouded the course at 1020 as practice runs were due to begin, and a spokesperson for the local organisers said that no decision about cancelling or postponing the event had yet been taken. REUTERS/Dylan Martinez (RUSSIA - Tags: OLYMPICS SPORT SNOWBOARDING ENVIRONMENT)