Stage

In the Dolomites, at the foot of the “Queen”: want to discover the marmolada?

  • 2 days
  • April, May, June, July, August
  • Nature and Parks

Honor to the Queen! The Marmolada, a fantastic limestone mountain that with its big glacier is the largest of the Dolomites. All around, as a fit corollary, the Dolomite mountains of Sella, Sasso Piatto and Sasso Lungo, and Pelmo, Civetta and Tofane. Carbonate, volcanic and mineral rocks make it possible to admire the Queen of the Dolomites with a special eye, listening to the geological stories that can only be told here.


Itinerary
• Departure from the dam of Lake Fedaia near the lift to Pian dei Fiacconi
• From Rifugio Ghiacciaio Marmolada located at 10 minutes distance from the lift uphill station, we follow the traces of the trail and the little "stonemen" toward the front of the glacier.
• We then return to Rifugio Ghiacciaio Marmolada following the same itinerary. From here, without taking the lift we used to get to the summit, we continue along trail 606 to return to the dam of Lake Fedaia.

1

Conca di Fedaia

At the head of Val di Fassa, 2053 m high, we find the Fedaia reservoir. The lake covers a surface of 625,000 m2 and has a volume of 16 million m3, and wets the northern slopes of the Marmolada. A gravity dam 56 metres tall built in 1955 by ENEL contains the waters. The water flows into the reservoir partly from the springs of Avisio, the Main Glacier of Marmolada and is also pumped from the Ombretta Creek. The large reservoir acts as head regulator for the hydroelectric plants of Cordevole.

Next to Lake Fedaia, towards the East, is the small lake of S. Maria di Fedaia, considered to be the spring of the River Avisio. It owes its origin to a moraine barrage. Its banks are open, slightly sloping and mostly grassy, with landslide boulders. It is fed by the waters of winter snow-melt and by the Main Glacier of Marmolada, as well as by non-perennial torrents that descend from the southern slope of Padon.

2

The first was not the last

At 2,486 m above sea level, on a rocky hill, lies the Col De Bous. During World War I, a large natural cavern at the foot of the West face of the hill was discovered by the Austrian military and transformed into a large and safe shelter by building shacks. The place was once crossed by a military via ferrata that led to a ledge to the North, where there was an observation post.

Near the saddle, the second section of the cableway arrived from the south; the cabelway originally took off from Pian Trevisan, the most important sorting centre for fresh soldiers and Austrian supplies for the Marmolada front. From the Col de Bous started the third cableway section that arrived to the West side of Sass da le Doudesc and at the Città di Ghiaccio (city of ice), a complex network of tunnels and trenches dug inside the Marmolada glacier. Living in the glacier meant taking shelter from the cold, from the danger of avalanches and from "enemy" artillery fire.

To the South, the saddle preserves the remains of an old shelter built after the war to replace the Austrian military buildings, that was later destroyed by fire in the 1930s.

3

The former glacier

Marmolada is a massive mountain formed by limestone referred to by geologists as the Marmolada Limestone. Here the layers appear as a dip-slope and are tilted North towards Lake Fedaia. The presence of this morphology has led to the birth of the largest glacier in the Dolomites.

Today, the Main Glacier of the Marmolada has a trapezoid shape with the largest side at the bottom and covering an area of 1.6 km2. Two imposing rocky ridges, Sasso delle Undici to the East and Sasso delle Dodici to the West, divide the glacier in three separate flows: the Eastern or Serauta, the Central and the Western. These distinct formations of the glacier's front today are no longer evident, due to the retraction of the ice caused by global warming.

Currently the minimum elevation of the central front is estimated at about 2,700 m. The frontal moraines of the Little Ice Age, formed by the glacier in 1859 at the end of its last and most important progression, are visible 500 m below. This data clearly shows the extent of the retraction that has taken place over the past 150 years, quantifiable in 500 m in altitude and about 1 km in the horizontal plane.

4

The wonder of being glaciologists

A glacier leaves clear traces of its passage. In several places, you can see polished rocky surfaces representing one of the classic signs of the passage of a glacier. These humps, often resembling the profile of a whale, are called roches moutonnées or "sheepback" rocks and are formed by the abrasive action of the embedded debris at the base of the glacier that crawled with force on the underlying rock, smoothening its surface.

The orientation of striations carved into the rock indicates the direction of the ice flow. Signs of Karst erosion are clearly visible on these "sheepback" rocks. On these rocks, you can recognise strange triangles drawn with red paint. These are the measuring points marked by glaciologists who with a metric tape annually measure the distance between this point and the glacier's front. The first measurements were taken in the 1950s by Enel (National electricity agency) employees, who were interested in the behaviour of the glacier, which with its melting water replenishes the Fedaia reservoir.

5

The skin of the glacier

A legend has it that an elderly peasant woman stubbornly insisted on collecting hay in a day dedicated to the patron saint of Canazei, the Madonna della Neve (August 1), disregarding the advice of her fellow citizens. As a form of divine punishment, the old lady was covered together with the mountain by an immense snowfall, which formed the glacier. Obviously this is not the case. Ice forms due to the accumulation and transformation of winter snow that persists even during the summer.

Now let's touch the ice! It appears rough, with debris inside and on top of it. On the surface there are "ice mushrooms", curious shapes linked to the presence of a boulder supported by a stalk of ice that cannot melt because of the boulder's protection. Where the slope increases, the surface of the ice fractures, forming crevasses. Small streams (bédières) sculpt the ice, and some of them end their path in the heart of the glacier through swallow-holes (glacier mills).

6

Acid!!!!

Waters that flow on the surface and disappear, swallowed underground. We are witnessing Karst erosion, that gives rise to the formation of an underground fairy-tale environment, with rivers, tunnels, huge caves, and that strikingly shapes the earth's crust, like the area we observe along the trail between Pian dei Fiacconi and Lake Fedaia.
The phenomenon occurs when slightly acidic water, like rainwater enriched by small amounts of carbon dioxide (CO2), encounters rocks composed of calcium carbonate (CaCO3). The acid water dissolves the calcium carbonate, transforming it into soluble bicarbonate (Ca(HCO3)2). This reaction is reversible; in other words, calcium carbonate can form again from bicarbonate and give rise to stalactites and stalagmites.
The erosive surface forms of Karst most common here, those formed by the dissolution of calcium carbonate, are the furrowed fields, showing ruts a few meters deep at the most, almost parallel and sometimes separated by ridges that can be sharp and pointy.