Ibones: what they are, characteristics, how they are formed and where they are found

An ibón is a lake of glacial origin found in the high areas of the Pyrenees. They were formed thousands of years ago, when glaciers excavated the terrain and, as they retreated, they left depressions that were filled with water from melting ice, rain or small streams.

However, many do not know the meaning of the specific word. The word “ibón” comes from Aragonese, the traditional language spoken in that region of the Pyrenees, and means precisely “mountain lake.” Over time, the term has stuck to refer specifically to these high-altitude lakes, which are often surrounded by rocky landscapes and spectacular views.

In this other article you can learn more about Glacial Lake: what it is and how it is formed.

The ibones have several characteristics that make them unique within the Pyrenean landscape. Firstly, they are usually found at high altitudes, usually above 1,500 meters, although some are even located above 2,500 meters. This means that the climate around them is cold for much of the year, which directly influences their appearance and the life they support. Many lakes remain frozen in winter and part of spring, and the water they contain is very cold and crystalline. Another of their peculiarities is the environment that surrounds them. Being located in high mountains, they are usually wedged between rocks, snowfields and alpine meadows.

Flora of the ibones

Their location and environment limit the type of flora that can grow near them. Among the flora of the ibones we can find that there are, on the shores and around the lakes, plants adapted to the cold, such as small alpine flowers, mosses and lichens that withstand humidity and low temperatures well.

Fauna of the ibones

As for the fauna of the lakes, there is not as much diversity as in the lakes in lower areas, precisely due to the extreme climate and the lack of nutrients in their waters. However, some very well adapted species live there, such as amphibians, such as Pyrenean newts and frogs, aquatic insects and small invertebrates. Nearby it is also possible to see marmots, chamois and mountain birds such as the bearded vulture or the golden eagle.

We also recommend you read this other article about the Flora and fauna of the Pyrenees.

The lakes were formed thousands of years ago, during the last glaciations that shaped the landscape of the Pyrenees. The process was:

1. Large masses of ice slowly descended down the mountains, acting like enormous “natural bulldozers.”
2. The weight and movement of these glaciers eroded the terrain, uprooting rocks and excavating depressions in the ground.
3. When the climate began to warm and the glaciers retreated, these cavities became free and began to fill with water from melting ice, rain, and mountain streams. The result was the creation of high mountain lakes.

There are several ways to classify them. For example, they can be classified according to their nature:

• Classic or natural glacial lakes: natural lakes formed by the erosion of ancient glaciers, such as the Ibón de Plan (Basa de la Mora), the Ibón de Anayet or the Ibón de Estanés.
• Dammed or modified lakes: they are natural glacial lakes to which a dam has been added to regulate their level, such as the Ibón de Estanés and the Ibón de Bachimaña Bajo.
• “chelaus” or frozen Ibones: those that remain frozen for much of the year due to their high altitude, covered by a characteristic bluish ice, which makes them very unique.

We can also classify them according to their location:

• High mountain lakes: located above 2,000 m, such as those in Anayet either Arrielsurrounded by steep peaks.
• Accessible or mid-mountain lakes: easier access and at a lower altitude, such as Ibón de Plan or the Ibón de Estanesideal for family excursions.
• Chained or group lakes: sets of lakes that form connected glacial systems, such as Bachimaña Ibones or the Arriel Ibones.
• Solitary lakes: isolated lakes in valleys or glacial cirques, such as the Ibón de Escarpinosawith great landscape and ecological value.

As we have mentioned before, the ibones are found mainly in the Pyrenees, both on the Aragonese and French sides and to a lesser extent on the Catalan side. They are exclusive high mountain lakes, so they always appear in elevated areas, surrounded by peaks, rock screes and alpine meadows.

Aragon, especially in the Pyrenees of Huesca, is where most of them are concentrated. There they can be found in places such as the Tena Valley, the Benasque Valley or the Balneario de Panticosa area, which are authentic ibones sanctuaries of the Pyrenees of Huesca.

Some well-known examples of making a lake route are:

• Ibón de Bachimaña
• Ibón de Sabocos
• Ibón de Estanes
• Anayet Ibones
• Ibón de Cregüeña
• Ibón de Plan or “Basa de la Mora”
• Ibón de Espelunciecha
• Piedrafita Lake

The lakes are not only beautiful lakes in the middle of the mountains, they also play a fundamental ecological role.

• Firstly, they function as freshwater reserves in high mountain areas. Their glacial origin and location mean that they accumulate meltwater and precipitation, which feeds streams and rivers that descend into the valleys. In this way, they contribute to maintaining the water balance of the entire Pyrenean basin.
• Furthermore, ibones are unique and fragile ecosystems. Although its waters are cold and poor in nutrients, they are home to unique species highly adapted to these extreme conditions. Some amphibians, such as the Pyrenean newt, can only live in environments of this type, making ibones key refuges for their survival.
• They also act as natural indicators of climate change. Due to their glacial origin and their location in high mountains, the lakes are very sensitive to temperature variations and the decline of glaciers. Observing changes in their water level, in the surrounding flora or in the fauna that inhabits them allows scientists to study how the climate is evolving in the Pyrenees.
• Finally, we cannot forget its cultural and landscape value. The ibones are part of the identity of the Pyrenees and have inspired legends, mountain routes and local traditions. In addition, they attract hikers, mountaineers and nature lovers, which reinforces their importance also in the tourist and economic sphere.

One of the main impacts of climate change on lakes is the retreat of glaciers, which reduces the supply of meltwater that feeds many lakes. This causes some to reduce their water level, partially dry out in summer or even disappear in extreme cases.

On the other hand, we have the increase in average temperature, which causes the lakes to remain frozen for less time per year. That early thaw alters the natural cycles of amphibians, insects and plants that depend on those cold, stable conditions.

A change is also observed in the flora and fauna of the lakes or high mountains. Some species adapted to the cold, such as the Pyrenean newt or certain alpine flowers, may be displaced by others that now find more favorable conditions at those heights, generating an imbalance in the ecosystem.

Yes, they are accessible via well-marked hiking trails and some even supported by ski lifts or chairlifts, making them suitable for families and hikers of all levels.

The best time to visit the lakes is summer. The weather is warmer and safer, and the trails are clear, making it easier to access and experience. The first half of September is especially attractive: the landscape is dyed in autumn tones and there is less influx of visitors.

• Ibón: is a mountain lake, generally small and natural, formed by the accumulation of meltwater in depressions created by ancient glaciers in the Pyrenees. The term, of Aragonese origin, refers specifically to these formations in that region.
• Glacial lake: natural body of water that is born by the retreat of a glacier, filling a depression carved by ice; Ibons are a specific type of glacial lakes located in high mountains, such as in the Pyrenees.
• Reservoir: The reservoir is an artificial lake created by the partial or total closure of a river channel, generally by means of a dam, for purposes such as water supply, electricity generation or irrigation.

If you want to read more articles similar to Ibones: what they are, characteristics, how they are formed and where they are found, we recommend that you enter our Ecosystems category.