The grotto, where the faithful believe that Marie-Bernarde Soubirous, later to become Saint Bernadette, saw 18 apparitions of the Virgin Mary, reopened to the public on Saturday morning after being closed for four days.
Along with most of the other religious sites and 37 hotels it was closed when violent storms and melting snow in the Pyrenees caused the Gave de Pau river to burst its banks, flooding much of the town.
With one subterranean church under 30-40cm of mud and widespread flood damage in the town, the authorities must now begin a major clean-up, repeating much of the work carried out after floods last October.
Roads to the last mountain villages that had been cut off by the storms were reopened Saturday morning.
Two stages of the Tour de France, which starts on 29 June, are planned to take place in
the Pyrenees, where the storms caused the most damage.
Earlier in the week Tour boss Christian Prudhomme said he would "wait a little" before deciding whether to change the route, possibly to avoid the Bagnères-de-Bigorre stage.
French farmers are counting the cost across, put at 500 million euros by one farmers’ union.
As well as damaging vineyards in the Loire and Cahors, the storms have prevented the planting of maze and harmed the production of other cereals and livestock feed is short.
The cherry crop in the Yonne region has been 80 per cent destroyed, farmers claim, but other fruits are believed to be little affected.
A flood alert for the Arc river in the French Alps was lifted Saturday.
The river, whose source is on the frontier with Italy and 2,800 metres, joins the Isère river, which flooded roads in Grenoble on Friday.