February 17 - After days of speculation about the negative impact of warm weather here, it has been the arrival of fog which has caused the first overnight delays of the Sochi 2014 Winter Olympics.
The men's 15-kilometre mass start biathlon was initially planned for yesterday evening but was repeatedly put back before being rearranged for today due to vision being unsuitable for skiing, spectating and particularly shooting.
But, with the weather failing to lift this morning, the event was eventually postponed overnight, while the men's snowboard cross was also rearranged for tomorrow following initial delays and the cancellation of the seeding run.
The postponements come after repeated queries over the impact of warm conditions and the likelihood of Sochi 2014 having to dig into their reserves of snow to ensure the necessary covering.
The situation was not missed by International Olympic Committee (IOC) spokesman Mark Adams who said this morning that he found it "actually quite ironic that the biggest issue we've had so far is due to winter fog and that's led to the biggest postponement we've had".
Organisers at the snowboard cross went to extreme lengths to ready the course, even turning on the snow gun fans in an apparent attempt to blow away the fog, which was particularly limiting conditions on the top part of the course.
But the postponement was met with approval by various athletes.
"I guess the maximum speed we reach is 80km per hour - there is no way of competing in fog - it's much too dangerous."
Similar acceptance was illustrated by French biathlete Martin Fourcade, who has already won two gold medals in Sochi, when he tweeted "well, I am going to sleep again - we'll see each other tomorrow!" after his race was postponed again.
The weather did lift by the evening however with medals action taking place in freestyle skiing, women's biathlon and aerials, as well as down in the Olympic Park cluster.
The biathlon is now due to get underway at 14:30 tomorrow , while the snowboard cross should start at 10:30 but will go straight into knock-out rounds, with athletes seeded based on their world ranking rather than the usual qualifying run.
With more rain and snow forecast tomorrow the start times for the women's giant slalom has also been brought forward by 90 minutes, with the first run now set for 09:30.
February 2014: IOC delighted with progress at halfway point of Sochi 2014
February 2014: Fourcade scoops second gold with dominant biathlon victory in heat