Col d'Allos is a high mountain pass at an elevation of 2.250m (7,382ft) above the sea level, located in the Alps in the department of Alpes-de-Haute-Provence in France. The pass is traversed by the D908, a road with numerous hairpins that bring you to the top. The road over the pass is closed from October to July.
The road is difficult and it’s a nightmare in the wet or dark (or both). The pass is located in the Parc National du Mercantour and connects Barcelonnette in the Ubaye Valley and Colmars and goes on to the Col des Champs.It lies parallel to the Col de la Cayolle and Col de la Bonette. Col d'Allos is one of the most popular mountain passes in the Tour de France. Like many of the passes in this area it owes its reason for being to military strategies, involving the defense from Italian and German attacks. Allos opened in 1891, 22 years before another option to cross this ridge via the Col de la Cayolle was added.
There are 3 possible routes to reach the top. Starting from Barcelonnette, at an elevation of 1,100m above the sea level, the ascent is 17.5 km long and the elevation gain is 1.108 meters. The average percentage is 6.3 %. This little sinuous road climbs along side a cliff high above a steep canyon and then hairpins over the mountain towards the mediterranean 100kms away. Starting from Allos, the ascent is 15 km long and the elevation gain is 805 meters. The average percentage is 5.4 %. The road is small and intimate and never getting too hard, so very enjoyable for climbers. After you"ve passed La Foux d"Allos, the climb becomes steeper with 7-8% average. And starting from Colmars, the ascent is 23.6 km long. Over this distance, the elevation gain is 1.005 meters and the average percentage is 4.3 %.