Grotte de la Glacière

Useful Information

Location: Bois de la Glacière, 25530 Chaux-lès-Passavant.
In the forest Chaux-Les-Passavant near Vercel. From Besançon 30 km on N57-D492-D30, from Baume-les-Dames 20 km on D50-D30, from le Saut-du-Doubs 50 km, from Belfort 80 km.
(47.248560, 6.364282)
Open: MAR to MAY daily 10-12, 14-18.
JUN to AUG daily 9-19.
SEP daily 10-12, 14-17.
OCT Mon-Sat 14-16, Sun 10-12, 14-17.
Fee: Adults EUR 6, Children (5-10) EUR 3.50, Children (0-4) free, Student EUR 5.
Groups (+): Adults EUR , Children (3-18) EUR .
Classification: SpeleologyKarst Cave Speleologyice cave.
Light: LightIncandescent Electric Light System
Dimension: A=525 m asl, VR=68 m, H=30 m.
Guided tours: D=40min, VR=61 m.
Photography: allowed
Accessibility: no
Address: Grotte de la Glacière et la Maison des Minéraux, Chaux-Les-Passavant, 25530 Vercel, Tel: +33-381-604426, Fax: +33-381-604344. E-mail: contact
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1584 visited by Boissent.
1592 visited by Gollut.
1686 visited by Boissot.
1712 mentioned in the Mémoires de l'Academie Royal des Sciences.
1743 visited by Charpentier de Cossigny.
1869 opened to the public.
1887 end of ice mining.
1910 trails damaged by flood.
1953 trails damaged by flood.


The Grotte de la Glacière (Ice Cave) is an ice cave of the cold trap type. The cave is a huge doline with vertical walls and a single chamber at the bottom. In winter cold air flows into the cave because it is heavier than the air inside, in summer there is no possibility for the cold air to escape or for warm air to enter. The same effect is used in refrigerator with a lid on top. Even if you leave it open, the cold air stays inside. In cold winters, the cave temperature reaches -25 °C at the bottom. On average, it is between -6° C and -2° C, but it becomes above 0 °C during summer. It is actually an equilibrium between growing and melting.

The cave is located in the Bois de la Glacière near Chaux-lès-Passavant. The doline is an opening with a diameter of 21 m. On one side a slope of debris was used to build a trail which goes down in serpentines into the cave. The bottom is reached 61 m below the surface.

Many caves contain ice flowstones in winter, but it is very rare if they stay all the year. The cave had great economic importance, as the ice could be sold well and the entire surrounding area was supplied with this valuable commodity. In the 16th century ice was delivered to the Notre-Dame de la Grâce-Dieu abbey, the people called the cave Froidière (Cooler). During the invasion of the Franche-Comté in the 17th century the cave was used as a hideout. In the 19th century, the collected ice was used as an anesthetic in hospitals and was used in the production of beer and cheese. The ice was isolated with straw and transported only during the night, and then stored in ice cellars. To increase the amount of ice, they pumped water into the cave during winter.

At the same time it was visited by numerous famous people, because it was considered the only "low altitude" ice cave in France. Obviously the trails were originally built to get the ice from the cave, but since 1869 the cave was open as a show cave. When the refrigerator was invented at the end of the 19th century, ice soon became cheap, and the ice mining was not profitable anymore. But there was still the touristic side, and as the trails were already there, it was simple to open it to the public.

But global warming has actually ended the effect, the cave is still cold, there is still ice, but it is not cold enough that it stays all year. The result is simple, during summer, when the ice would be most impressive, it is actually gone. Spectacular pictures with ice are made during winter. Once there was a 30 m thick layer of ice in the cave, during wither it reached the ceiling. The mining reduced the ice, but it still regrew every winter. But frequent summers with temperatures above 4 °C during summer cause the reduction of the ice. In 2015 only 500 m³ were still there.

The obvious thing, to blame the global warming alone, is actually not valid. According to Charpentier de Cossigny, who visited the cave in 1743, the cave was completely emptied of its ice in 1727 and in 1743 the cave was again completely filled with ice. And in the mid 20th century the owners installed water pipes to create more ice during winter. This would still work today, but it's probably too expensive, or it is not allowed any more because of nature protection law.

The results are obvious: the cave is not visited any more, with too few visitors it is hard to finance necessary repairs. This cave is deteriorating, trails are only repaired if it is absolutely necessary, and in the cheapest way possible. The low part of the cave where the last remaining ice could be found, is not accessible anymore. If this is really because of nature protection, or for security reasons due to a lack of renovation, remains unclear. Nevertheless, no ice, no visitors. They abandoned their website to save a few bucks, the guides are disillusioned, and the few visitors disappointed, writing bad reviews on travel portals. The deterioration gathers momentum.

We find this cave is spectacular, and the ice is just an additional feature. We recommend to visit the cave, as long as it's still possible, because its definitely worth the effort. The huge space, the cold air, the fog, the speleothems, calcite crystals in cracks, fossils in the walls. This cave has a lot to offer. Unfortunately we think that it could be closed for good in a few years, which is quite sad.

This is the only ice cave of its type in France. Inhabited in prehistoric times it was first visited in the 16th century by Boissotnot in 1584 by Gollut in 1592 and Boissot in 1686. Later it was visited by E A Martel and Fornier who studied the temperature, and the glacial phenomena. The cave has also attracted the attention of scientists and poets, who have come to marvel at the rich decorations.

At the entrance there is the Maison des Mineraux - a Museum of Minerals with samples of over 500 minerals from all over the world. Admission free.

Text by Tony Oldham (2003). With kind permission.