Avalanche gallery at Roc de Carroux secures RN‑320 access between France and Andorra

The new avalanche gallery at the Roc de Carroux provides a permanent solution to the recurrent closures that have affected the RN-320 access road between France and Andorra. The roughly ten-kilometre stretch between L’Hospitalet and Pas de la Casa crosses about thirty avalanche corridors and is exposed to freeze–thaw cycles that increase the risk of rockfalls; one of the most vulnerable points was the hairpin bend beneath the Roc de Carroux slope, around one kilometre from L’Hospitalet.

Since the road opened in 1978, various measures have been tried to protect users. In the 1980s authorities installed an explosive-triggering system to provoke controlled avalanches, but that method proved inadequate against wet, heavy avalanches or those caused by melting at the slope base, which are hard to predict and to trigger safely. Over the past three decades, ten avalanches have reached the road; the last major incident, in 2015, carried a car some 100 metres but caused no fatalities and forced a ten-day closure.

In those conditions, preventive detonations could not guarantee continuous safety, and only closing the road would reliably protect users. The newly inaugurated gallery removes the need for repeated closures by shielding the circulation from avalanches and rockfalls at the most exposed section.

Construction of the gallery followed an international agreement signed in 2017 and was financed jointly by France and Andorra on an equal basis. For Andorra, this is the first time the government has funded infrastructure located outside its territory, a strategic decision justified on the grounds of protecting the country’s economy and the livelihoods tied to traffic through Pas de la Casa.

Xavier Espot, Andorra’s head of government, described the opening as an important day for the country, noting the direct economic and social benefits of the investment. Officials say the project not only resolves a long-standing logistical problem but also reinforces bilateral cooperation by addressing a shared interest in keeping the cross-border route reliably open.

Authorities expect the gallery to significantly reduce winter disruptions and improve road safety for drivers travelling between France and Andorra.