Duration: Approximately 3.5 to 4 hours of narrated hiking Distance: 11 km (loop from Ritom funicular upper station) Elevation Gain: 450 m ascent / 450 m descent Starting Elevation: 1,794 m (Piora funicular upper station) High Point: 2,150 m (Cadagno di Fuori area) Difficulty: T2 (moderate mountain hiking) Best Season: June to October GPS Start: 46.5260N, 8.6850E (Piora upper station) GPS Lago Ritom: 46.5225N, 8.6920E GPS Lago di Cadagno: 46.5500N, 8.7140E
Introduction
Welcome to one of the Ticino's hidden treasures: the Val Piora and its remarkable chain of alpine lakes, beginning with the Lago Ritom and extending to the scientifically famous Lago di Cadagno. You have arrived here by one of the most remarkable pieces of engineering in Switzerland: the Ritom funicular railway, the steepest in the world.
The Ritom funicular, built in 1921 for the construction and maintenance of the hydroelectric dam at Lago Ritom, climbs 786 metres in just 1.4 kilometres, at a maximum gradient of 87.8 percent. That is nearly vertical. As you rode up, you tilted backward at an angle that makes conventional railways seem flat. The funicular was originally a purely industrial installation, but its spectacular route and the beauty of the landscape at the top led to its opening for tourist use.
The Val Piora is a high Alpine valley running roughly east-west at an elevation of 1,800 to 2,200 metres. It is the largest of the high valleys in the Lepontine Alps of the Ticino, and it contains a chain of small lakes of extraordinary ecological and scientific interest. The valley is a natural laboratory for research in limnology, the study of lakes, and the Alpine Biology Centre at Cadagno has been conducting research here since the 1930s.
Today's hike is a loop from the Ritom funicular upper station through the Val Piora, visiting Lago Ritom, Lago di Tom, and Lago di Cadagno before returning. The total distance is approximately 11 kilometres with 450 metres of cumulative elevation change. The terrain is gentle by Alpine standards, and the trail is well-marked.
Practical notes: The funicular runs from Piotta, near Airolo, at the southern end of the Gotthard Pass road. The schedule is seasonal, typically from June to October, with reduced service in shoulder months. Carry water, food, sun protection, and rain gear. The valley is exposed and can be windy.
Waypoint 1: Piora Funicular Upper Station (1,794 m)
GPS: 46.5260N, 8.6850E
Step off the funicular and catch your breath, both from the steep ride and from the view. The Lago Ritom stretches before you, its dark blue waters filling a natural basin that has been enlarged by a dam. The peaks of the Lepontine Alps frame the scene, their grey granite slopes rising above green meadows.
The Ritom dam, built between 1917 and 1920, raised the lake's level by about 8 metres and increased its volume significantly. The water is used for hydroelectric power generation at the Ritom power station in Piotta below. The dam is relatively modest by Swiss standards, a gravity dam of concrete and masonry, but its location at nearly 1,800 metres makes it one of the higher dams in the Ticino.
The rock here is very different from the limestone of the northern Alps. The Val Piora lies in the Gotthard Massif, and the bedrock is primarily gneiss and granite, crystalline rocks that are over 300 million years old. These ancient rocks give the landscape a distinctive character: rounded, glacially smoothed forms, scattered boulders of grey granite, and a soil that is acidic and nutrient-poor.
However, the Val Piora has a geological surprise. A band of dolomite, a magnesium-rich limestone, cuts across the valley. Where this dolomite outcrops, the landscape changes dramatically: the soil becomes alkaline, the flora shifts to lime-loving species, and the lake chemistry changes. This geological boundary is one of the keys to understanding why the Val Piora's lakes are so scientifically interesting.
Begin walking east along the northern shore of Lago Ritom.
Next waypoint: 1.5 km, approximately 20 minutes.
Waypoint 2: Lago Ritom Eastern Shore (1,800 m)
GPS: 46.5225N, 8.6920E
Walking along the northern shore of Lago Ritom, you pass through alpine meadow and low shrubs. The lake on your left is roughly 1.5 kilometres long and 500 metres wide, with a maximum depth of about 69 metres.
The dark colour of the water reflects the granitic bedrock, which contributes few dissolved minerals. The lake is classified as oligotrophic, meaning it has low nutrient levels, which limits algal growth and keeps the water clear. Fish have been stocked in the lake, and anglers come for trout and Arctic char.
The meadows along the shore are dotted with wildflowers. In July, look for the bright blue of the spring gentian, the yellow of the alpine hawkweed, and the white plumes of cotton grass in boggy areas. Cotton grass, Eriophorum species, is actually a sedge, not a grass, and its distinctive fluffy seed heads are one of the characteristic sights of alpine wetlands.
The wetland areas around the lake are ecologically important. They provide breeding habitat for the common frog and the alpine newt, and they are visited by wading birds during migration. The common snipe, with its distinctive "drumming" display flight, can sometimes be heard in spring and early summer.
Next waypoint: 1.5 km, approximately 25 minutes.
Waypoint 3: Lago di Tom (1,855 m)
GPS: 46.5310N, 8.6990E
The trail continues east from Lago Ritom to the Lago di Tom, a smaller, shallower lake at 1,855 metres. This lake is unnamed on some maps, sometimes labelled simply as a pond, but it has its own quiet beauty.
Lago di Tom lies on the granitic bedrock, and its water is correspondingly acidic and low in minerals. The shore is rocky, with patches of peat bog where sphagnum mosses grow. Peat bogs are among the most threatened habitats in Switzerland, as many lower-altitude bogs have been drained for agriculture. These high-altitude bogs are among the last remnants of a habitat that was once widespread.
The bog vegetation includes several specialised species. Sundews, Drosera rotundifolia, tiny carnivorous plants with sticky, glistening leaves that trap and digest insects, grow in the wettest areas. The insects provide nitrogen and phosphorus that the plants cannot obtain from the nutrient-poor bog soil. If you look carefully at the boggy margins of the lake, you may spot the red-tinged rosettes of sundew leaves among the sphagnum moss.
The transition from the granite zone to the dolomite zone begins near here. As you continue east, you will notice the soil colour changing from grey-brown to more yellowish tones, and the vegetation shifting in character.
Next waypoint: 1.5 km, approximately 25 minutes.
Waypoint 4: The Geological Boundary (1,900 m)
GPS: 46.5380N, 8.7040E
You are now crossing one of the most scientifically significant geological boundaries in the Swiss Alps. Underfoot, the bedrock transitions from the ancient gneiss and granite of the Gotthard Massif to a band of Triassic dolomite, a magnesium-rich carbonate rock roughly 230 million years old.
This geological change has profound effects on everything above it. The soil on dolomite is alkaline, lighter in colour, and richer in calcium and magnesium. The vegetation changes noticeably: lime-loving species appear, including the alpine aster, the mountain avens, and the edelweiss, none of which grow on the acidic granitic soils just a few hundred metres back.
The most famous consequence of this geological boundary is its effect on the Lago di Cadagno, which sits directly on the dolomite. The alkaline, mineral-rich water that percolates through the dolomite feeds the lake from below, creating conditions utterly different from the acidic, mineral-poor lakes of the granitic zone.
The Val Piora is a paradise for geologists. The collision of these different rock types, visible in the landscape and in the ecology, makes it one of the best places in the Alps to study the relationship between geology, soil, water chemistry, and biology. Research stations and universities have been studying these connections here for decades.
Next waypoint: 1.5 km, approximately 25 minutes.
Waypoint 5: The Alpine Biology Centre and Cadagno (2,000 m)
GPS: 46.5450N, 8.7095E
The small settlement of Cadagno di Dentro sits near the Alpine Biology Centre, a research station operated jointly by the University of Zurich and the Swiss Academy of Sciences. The centre has been conducting research in the Val Piora since the 1930s, focusing on the limnology, ecology, and geology of the valley.
The buildings here are a mix of traditional alpine structures and modern research facilities. The research station, modest in appearance, has hosted scientists from around the world who come to study the unique lakes, wetlands, and ecosystems of the Val Piora.
Cadagno di Dentro also has a small chapel and a few traditional stone buildings. The settlement was historically a summer grazing station, and it retains a simple, utilitarian character. The stone buildings, with their thick walls and small windows, were designed to withstand harsh winters and heavy snowfall.
Nearby, the Capanna Cadagno, a mountain hut of the Ticino section of the Swiss Alpine Club, offers meals and dormitory accommodation. If the hut is open, a plate of polenta with local cheese or sausage, a Ticinese mountain speciality, is a fine reward for the walk.
Next waypoint: 800 m, approximately 15 minutes.
Waypoint 6: Lago di Cadagno (1,987 m)
GPS: 46.5500N, 8.7140E
You have reached the Lago di Cadagno, a lake that is famous among limnologists worldwide for a phenomenon found in only a handful of lakes on Earth: a permanent layer of purple sulphur bacteria suspended in its water column.
The lake is meromictic, meaning its water column is permanently stratified into layers that do not mix. The upper layer is oxygenated and fed by surface streams. The lower layer is anoxic, lacking oxygen, and fed by mineral-rich water that wells up through the dolomite bedrock. At the boundary between these layers, a dense population of purple sulphur bacteria, Chromatium okenii, thrives, living off the hydrogen sulphide that rises from the anoxic depths. These bacteria use sulphide instead of water in their photosynthesis, a metabolic pathway that may have been among the earliest forms of photosynthesis on Earth, predating the oxygen-producing photosynthesis of plants by billions of years.
The bacterial layer is visible as a pinkish-red band in the water when viewed from certain angles or in sample bottles. Its permanent presence in the Lago di Cadagno makes this one of the most important natural laboratories for studying ancient microbial ecosystems. Scientists here study the bacteria as living analogues of organisms that dominated the Earth's biosphere billions of years ago, during the Proterozoic era.
The lake is roughly 800 metres long and 350 metres wide, with a maximum depth of 21 metres. Its surface waters are clear and support trout and char, while the deep anoxic zone is effectively a different world, hostile to most multicellular life but home to thriving microbial communities.
Walk around the southern shore for the best views. The lake reflects the surrounding peaks beautifully, and on calm days the water's surface shows a subtle iridescence from the bacterial layer below.
Next waypoint: Begin return via southern trail. 2.5 km, approximately 40 minutes.
Waypoint 7: The Southern Return Trail (1,950 m)
GPS: 46.5400N, 8.7050E
The return to the Ritom funicular follows a trail along the southern side of the valley, offering different perspectives on the landscape you explored on the way out. The views across the Val Piora to the peaks of the northern rim are particularly fine in the afternoon light.
The southern slopes of the valley are drier and warmer than the northern slopes, and the vegetation reflects this. The grasses are shorter and more wiry, and drought-tolerant species like thyme and rockrose appear. In the rock crevices, look for the sticky catchfly, Lychnis viscaria, with its pink flowers and sticky stems.
The panorama from the southern trail includes views south toward the Leventina valley and the main Gotthard route. The Leventina, the main north-south valley of the Ticino, carries the Gotthard road and railway, the lifelines connecting northern and southern Switzerland. The valley drops steeply from the Gotthard Pass to Bellinzona, losing nearly 2,000 metres in about 40 kilometres.
The cultural history of the Val Piora is rich despite its apparent remoteness. The valley has been used for summer grazing since at least the Middle Ages, and the traditional stone huts and walls you see scattered across the slopes are evidence of centuries of pastoral activity. The local dialect, Ticinese Italian, preserves vocabulary related to alpine farming that has disappeared from standard Italian, a linguistic fossil as interesting in its way as the geological fossils in the dolomite.
The Gotthard region, visible to the west, has been the most strategically important mountain area in Switzerland for over 700 years. Control of the Gotthard Pass, which connects the German-speaking north with the Italian-speaking south, was one of the primary motivations behind the founding of the Swiss Confederation. The first road over the pass was built in the thirteenth century, and the pass has been a commercial and military corridor ever since.
The Gotthard Base Tunnel, opened in 2016 at 57.1 kilometres, passes directly beneath the mountains you can see from this trail. It is the longest railway tunnel in the world and represents the latest chapter in over seven centuries of engineering efforts to conquer the Gotthard barrier. The trains passing through the tunnel far below your feet travel at speeds of up to 250 kilometres per hour, completing in minutes a journey that once took days of dangerous mountain travel.
The wildlife on the southern slopes includes the rock ptarmigan in winter, though in summer the bird is more easily found at higher elevations. Snow finches, recognisable by their white wing patches, are common among the rocky terrain, and the alpine accentor, a sparrow-sized bird with a streaked breast, feeds unobtrusively on the ground among the rocks and scrub.
Next waypoint: 2.5 km, approximately 40 minutes.
Waypoint 8: Return to Piora Station (1,794 m)
GPS: 46.5260N, 8.6850E
You have returned to the Ritom funicular upper station. The loop through the Val Piora is complete. Before taking the funicular down, look back across the valley one last time. The chain of lakes, each with its own character and colour, stretches across the landscape like jewels on a string. The Val Piora is a place that combines the wild beauty of the high Alps with scientific significance that reaches far beyond its modest scale.
Closing
You have walked through one of the most scientifically important alpine valleys in Switzerland, visiting lakes that range from simple granitic tarns to a globally significant natural laboratory of microbial ecology. The Val Piora is a place where geology, chemistry, and biology intersect in ways that are visible and tangible, a living textbook of alpine natural history.
The Ritom funicular descends to Piotta in about 12 minutes. From Piotta, it is a short walk to the Airolo railway station, where trains run north through the Gotthard tunnel to Goeschenen and Zurich, or south to Bellinzona and Lugano.
If you are continuing south, the Leventina valley offers several attractions: the medieval fortress of Castelgrande in Bellinzona, the subtropical gardens of Locarno, and the lakeside beauty of Ascona and the Brissago Islands.
Thank you for hiking with ch.tours. The purple bacteria of the Lago di Cadagno have been living their quiet, ancient lives in these waters for thousands of years. They will be here long after we are gone, a reminder of the deep time that underlies every mountain landscape. Safe travels.