The Borna da Ghiasa of Emarèse: the "Ice Hole" of the Aosta Valley
A hidden corner of nature, between history, geology and authentic wonder
There are places in the Aosta Valley that don't make noise. They don't appear on the most popular "must-see" lists, they don't fill the covers of travel magazines — and yet they stay with you longer than many famous destinations.
The Borna da Ghiasa of Emarèse is one of these places.
A little secret hidden among the woods above the village of Erésaz, in the municipality of Emarèse, where the mountain tells a silent story made of rock, cold air and human ingenuity. If you are staying at one of our ABC Vacanze properties and are looking for an original day trip, away from the beaten track but capable of delivering authentic emotions, this itinerary is made for you.
What is the Borna da Ghiasa?
"Borna da Ghiasa" in the local Valdostan dialect literally means "ice hole".
And that is exactly what you will find: a crack in the rock, about thirty metres deep, from which — even in the height of summer, when outside temperatures can reach 30°C (86°F) — a stream of icy cold air flows out, with temperatures close to zero. An almost surreal sensation, as if the mountain itself were breathing winter.
It's not magic, even though the effect is truly remarkable. The phenomenon is linked to a system of deep fractures in the subsoil, created by what geologists call DGPV (Deep Gravitational Slope Deformation): the extremely slow downward sliding of the entire Emarèse hillside, a movement triggered thousands of years ago by the retreat of an ancient glacier. In simple terms, air enters through fractures at a higher altitude, cools down on its long journey through the rock, and emerges — ice cold — from the opening at a lower altitude. A perfectly functioning natural refrigerator, created by nature itself.
For a long time, people believed that a subterranean glacier lay hidden beneath Emarèse. The reality, as often happens, turns out to be even more fascinating.
A village refrigerator: history and curiosities
The Borna da Ghiasa is not just an extraordinary geological phenomenon. It is also a genuine piece of local history.
For centuries, the inhabitants of Erésaz took advantage of this natural feature as a natural cold storage to preserve food during the hot summer months. At the entrance to the cavity, you can still see the remains of a wooden door dated 1892, which was once kept locked — and the key was held by the village parish priest, who controlled access. A small detail that speaks volumes about a distant world built on community spirit and simple but ingenious solutions.
A chronicle from 1871 records some remarkable data: with 32°C (90°F) measured outside, the temperature inside the cavity was just 0.5°C (33°F) — a difference of over thirty degrees, extraordinary and invaluable for a mountain community in the nineteenth century. The same account notes that the depth of the hole was measured at 29.73 metres, though without certainty that the lowered rope had actually reached the bottom.
Even Giuseppe Corona, in his celebrated Dans la Vallée d'Aoste. Manuel du Touriste (1882), was already recommending a visit to Emarèse, noting the presence of «une grotte naturelle avec un glacier perpétuel très curieux» — a natural cave with a very curious eternal glacier. The Borna da Ghiasa was fascinating travellers back in the nineteenth century: one more reason to go and discover it for yourself.
The trail: short, easy and full of atmosphere
The good news is that you don't need to be an experienced hiker to get there. The route is suitable for everyone, including families with older children, and offers rewarding scenery from the very first steps.
Getting there by car
Take the A5 motorway and exit at Châtillon/Saint-Vincent. Follow the signs for Saint-Vincent, then for the Col de Joux and Emarèse. After approximately 25 minutes on a scenic mountain road, you will reach the hamlet of Erésaz (1,187 m / 3,894 ft). Park near the Centre d'études Abbé Trèves and follow the trail sign marked "Borna da Ghiasa".
Where is it exactly? Emarèse is located in the central Aosta Valley, between the well-known towns of Châtillon and Saint-Vincent, roughly 1.5 hours from Turin and 2 hours from Milan by motorway.
Trail information
Start Erésaz, 1,187 m (3,894 ft)
End Borna da Ghiasa, ~1,310 m (4,298 ft)
Elevation gain ~130 m (427 ft)
Duration (outward) 25–30 minutes
Duration (return) 15–20 minutes
Trail marker No. 6
Difficulty Easy – Hiking (E)
Best season April – November
The walk
The cobbled path climbs gently between the houses and kitchen gardens of the village to a small stone bridge, then cuts across open meadows before entering a beautiful conifer forest. The light softens, the sounds of the world fade away. Shortly before reaching the destination, a brief steeper and rockier stretch — requiring a little care — will lead you to the entrance of the cavity.
And then, suddenly, the discovery: that breath of icy air rising from the rock, even in the middle of August.
Best time to visit: summer, when the contrast between the warm sunshine and the glacial air flowing from the fissure is truly spectacular. The trail can also be walked in winter when there is no snow on the ground.
Important: entering the cavity is not recommended due to the risk of rockfall. The magic is fully felt right at the entrance. Along the trail, a sign warns of the possible presence of asbestos fibres in the surrounding area, a legacy of a mining site that operated between 1872 and 1968 to the north of the route.
A territory full of surprises
Emarèse is a municipality that never stops surprising, and the Borna da Ghiasa is just one of its many curiosities. Nearby you will also find the Lago di Lot, known as the "Ghost Lake" because it only fills with water sporadically — according to local legend, its appearance announces a favourable period — and the Bec de l'Uja, a striking rocky pinnacle shaped like an eagle's beak, silently watching over the valley below.
A landscape that brings together geology, legend and local culture in a completely original way. Not a "quick photo stop", but one of those experiences that adds real depth to a journey.
Where is the Aosta Valley and why visit?
For those who are not yet familiar with the region: the Aosta Valley (Valle d'Aosta in Italian, Vallée d'Aoste in French) is the smallest and most mountainous region of Italy, nestled in the north-western Alps, bordering France and Switzerland. It is home to some of the highest peaks in Europe, including Mont Blanc, the Matterhorn, Monte Rosa and Gran Paradiso.
The region is renowned for its stunning alpine scenery, medieval castles, ancient Roman ruins, traditional cuisine and a rich bilingual culture — Italian and French are both official languages. Beyond the ski slopes and famous summits, the Aosta Valley hides countless lesser-known treasures like the Borna da Ghiasa, waiting to be discovered by curious travellers.
Discover it with ABC Vacanze
Our properties in the Aosta Valley — three hotels and a holiday home — are the ideal base for exploring not only the most celebrated destinations in the region, but also these authentic, off-the-beaten-track corners that make the Aosta Valley truly unique.
Between a day in the mountains and an evening enjoying local food and wine, a stop like the Borna da Ghiasa can make all the difference. It is in the quiet places, the ones that don't make noise, that you often find the most memorable stories.
Book your stay with ABC Vacanze and let yourself be surprised: the Aosta Valley always has something new to share.
The Borna da Ghiasa of Emarèse is one of these places.
A little secret hidden among the woods above the village of Erésaz, in the municipality of Emarèse, where the mountain tells a silent story made of rock, cold air and human ingenuity. If you are staying at one of our ABC Vacanze properties and are looking for an original day trip, away from the beaten track but capable of delivering authentic emotions, this itinerary is made for you.
What is the Borna da Ghiasa?
"Borna da Ghiasa" in the local Valdostan dialect literally means "ice hole".
And that is exactly what you will find: a crack in the rock, about thirty metres deep, from which — even in the height of summer, when outside temperatures can reach 30°C (86°F) — a stream of icy cold air flows out, with temperatures close to zero. An almost surreal sensation, as if the mountain itself were breathing winter.
It's not magic, even though the effect is truly remarkable. The phenomenon is linked to a system of deep fractures in the subsoil, created by what geologists call DGPV (Deep Gravitational Slope Deformation): the extremely slow downward sliding of the entire Emarèse hillside, a movement triggered thousands of years ago by the retreat of an ancient glacier. In simple terms, air enters through fractures at a higher altitude, cools down on its long journey through the rock, and emerges — ice cold — from the opening at a lower altitude. A perfectly functioning natural refrigerator, created by nature itself.
For a long time, people believed that a subterranean glacier lay hidden beneath Emarèse. The reality, as often happens, turns out to be even more fascinating.
A village refrigerator: history and curiosities
The Borna da Ghiasa is not just an extraordinary geological phenomenon. It is also a genuine piece of local history.
For centuries, the inhabitants of Erésaz took advantage of this natural feature as a natural cold storage to preserve food during the hot summer months. At the entrance to the cavity, you can still see the remains of a wooden door dated 1892, which was once kept locked — and the key was held by the village parish priest, who controlled access. A small detail that speaks volumes about a distant world built on community spirit and simple but ingenious solutions.
A chronicle from 1871 records some remarkable data: with 32°C (90°F) measured outside, the temperature inside the cavity was just 0.5°C (33°F) — a difference of over thirty degrees, extraordinary and invaluable for a mountain community in the nineteenth century. The same account notes that the depth of the hole was measured at 29.73 metres, though without certainty that the lowered rope had actually reached the bottom.
Even Giuseppe Corona, in his celebrated Dans la Vallée d'Aoste. Manuel du Touriste (1882), was already recommending a visit to Emarèse, noting the presence of «une grotte naturelle avec un glacier perpétuel très curieux» — a natural cave with a very curious eternal glacier. The Borna da Ghiasa was fascinating travellers back in the nineteenth century: one more reason to go and discover it for yourself.
The trail: short, easy and full of atmosphere
The good news is that you don't need to be an experienced hiker to get there. The route is suitable for everyone, including families with older children, and offers rewarding scenery from the very first steps.
Getting there by car
Take the A5 motorway and exit at Châtillon/Saint-Vincent. Follow the signs for Saint-Vincent, then for the Col de Joux and Emarèse. After approximately 25 minutes on a scenic mountain road, you will reach the hamlet of Erésaz (1,187 m / 3,894 ft). Park near the Centre d'études Abbé Trèves and follow the trail sign marked "Borna da Ghiasa".
Where is it exactly? Emarèse is located in the central Aosta Valley, between the well-known towns of Châtillon and Saint-Vincent, roughly 1.5 hours from Turin and 2 hours from Milan by motorway.
Trail information
Start Erésaz, 1,187 m (3,894 ft)
End Borna da Ghiasa, ~1,310 m (4,298 ft)
Elevation gain ~130 m (427 ft)
Duration (outward) 25–30 minutes
Duration (return) 15–20 minutes
Trail marker No. 6
Difficulty Easy – Hiking (E)
Best season April – November
The walk
The cobbled path climbs gently between the houses and kitchen gardens of the village to a small stone bridge, then cuts across open meadows before entering a beautiful conifer forest. The light softens, the sounds of the world fade away. Shortly before reaching the destination, a brief steeper and rockier stretch — requiring a little care — will lead you to the entrance of the cavity.
And then, suddenly, the discovery: that breath of icy air rising from the rock, even in the middle of August.
Best time to visit: summer, when the contrast between the warm sunshine and the glacial air flowing from the fissure is truly spectacular. The trail can also be walked in winter when there is no snow on the ground.
Important: entering the cavity is not recommended due to the risk of rockfall. The magic is fully felt right at the entrance. Along the trail, a sign warns of the possible presence of asbestos fibres in the surrounding area, a legacy of a mining site that operated between 1872 and 1968 to the north of the route.
A territory full of surprises
Emarèse is a municipality that never stops surprising, and the Borna da Ghiasa is just one of its many curiosities. Nearby you will also find the Lago di Lot, known as the "Ghost Lake" because it only fills with water sporadically — according to local legend, its appearance announces a favourable period — and the Bec de l'Uja, a striking rocky pinnacle shaped like an eagle's beak, silently watching over the valley below.
A landscape that brings together geology, legend and local culture in a completely original way. Not a "quick photo stop", but one of those experiences that adds real depth to a journey.
Where is the Aosta Valley and why visit?
For those who are not yet familiar with the region: the Aosta Valley (Valle d'Aosta in Italian, Vallée d'Aoste in French) is the smallest and most mountainous region of Italy, nestled in the north-western Alps, bordering France and Switzerland. It is home to some of the highest peaks in Europe, including Mont Blanc, the Matterhorn, Monte Rosa and Gran Paradiso.
The region is renowned for its stunning alpine scenery, medieval castles, ancient Roman ruins, traditional cuisine and a rich bilingual culture — Italian and French are both official languages. Beyond the ski slopes and famous summits, the Aosta Valley hides countless lesser-known treasures like the Borna da Ghiasa, waiting to be discovered by curious travellers.
Discover it with ABC Vacanze
Our properties in the Aosta Valley — three hotels and a holiday home — are the ideal base for exploring not only the most celebrated destinations in the region, but also these authentic, off-the-beaten-track corners that make the Aosta Valley truly unique.
Between a day in the mountains and an evening enjoying local food and wine, a stop like the Borna da Ghiasa can make all the difference. It is in the quiet places, the ones that don't make noise, that you often find the most memorable stories.
Book your stay with ABC Vacanze and let yourself be surprised: the Aosta Valley always has something new to share.
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Nice and friendly hotel, great breakfast
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Easter Ski Trip
Easter Ski Trip
Happy Vacation in Hotel L'Aiglon.
Happy Vacation in Hotel L'Aiglon.
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Nice location, great value
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Excellent séjour à l'hôtel l'Aiglon!
Friendly familystyle hotel
Friendly familystyle hotel
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Fabulous return visit
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Another GREAT stay