Tour de France officials said Tuesday they were \"not worried\" by snowfall high up in the Alps a day before the peloton tackles three days in the mountains. Some of the highest peaks in the Alps have been subject to snow in recent days, prompting fears that stages may have to be changed. Race course director Jean-Francois Pescheux said organisers were keeping a close watch on weather conditions and would make \"arrangements when and if necessary\". But he added: \"We know it can snow in the highest mountains, at least once a month in the summer. \"There\'s been snowfall, but normally it will disappear. I\'m not worried.\" While Wednesday\'s 16th stage finishes downhill at Pinerolo in Italy, stages 17 and 18 finish on the summits of the Galibier and Alpe d\'Huez respectively. On Thursday the peloton will tackle the high mountain passes of the Agnel (2,744 metres altitude) and the Izoard (2,360m) before the long climb to the Galibier whose summit is at 2,645m. A day later the peloton climbs the Galibier from the other direction, reaching an altitude of 2,556 before descending and then climbing the 14km to the summit of Alpe d\'Huez at 1,850 metres. Pescheux said organisers were taking things \"day by day\". \"For the moment we\'re just waiting. We will take things day by day,\" added Pescheux. \"What is problematic is if the snowfall makes the road so bad we can\'t race. But if that happens, we will make the necessary arrangements. \"We\'re not going to start imagining all sorts of disaster scenarios. When a decision is needed, we will make it.\" Pescheux added that ultimately, snowfall should not force the cancellation of stages on the world\'s premier cycling event. \"Contrary to other sports, cycling just doesn\'t come to a halt because of the weather conditions,\" he added. \"There would really need to be heavy snow or black ice for us to stop the race.\" The three stages in the Alps will decide the yellow jersey. Before the end of Tuesday\'s 16th stage to Gap Spain\'s Alberto Contador, the three-time and defending champion, trailed Frenchman Thomas Voeckler by 4min. The Saxo Bank leader\'s biggest concern, however, is how to claw back deficits of 2:11, 1:54 and 1:45 and to Frank Schleck, Cadel Evans and Andy Schleck respectively, considered his biggest rivals.