Lac du Génépy
AUSSOIS
Network
Lac du Génépy
Challenging
Difficulty6h30
Duration14,3km
Distance+910m
Positive Elevation-913m
Negative ElevationLoop
Course typeEmbed this item to access it offline
The date on the calendar indicated the 14th July on this morning... There is not a ripple of water on the Génépy lake despite the gusting northerly winds. This is because a thick layer of ice covers the lake. The varying colours of the mineral world around me transect the swirls of fresh snow. This is where you go up to the Lac du Génépy, starting out from the forest in your short sleeves until you end up thinking you’re crossing the rocky stretches of Iceland, where the plants have adapted in mad-cap fashion to cling to these rocky mounds. Here the birds no longer sing, only the ringing sounds of the alpine choughs and the guttural sounds of the ptarmigan resonate. Mathieu Beurier – National Park Ranger
21 points of interest
Fauna
The spotted nutcracker
This bird, with its robust beak and aptitude at opening the cones of the cembro pine, feeds almost exclusively on its seeds. It alerts visitors to the forest of its presence by its gravelly and discordant cry. Ÿou may be able to see the spotted nutcracker towards the end of summer, flitting from one pine to another to extract its seeds. He then hides them in bundles in the soil which he will then find again in the winter. The spotted nutcracker is able to memorise several hundred of these hiding places and find them under the snow. The very few caches that have been forgotten will perhaps provide new small cembro pines. The cembro pines benefit greatly from this association, known as symbiosis.
Flora
The lilium martagon
In June to July when you leave the forest and set foot on the mountain pastures, you may find a large plant with purple flowers. The lilium martagon, a rare species, colonises the clearings of the forest boundary. It favours so-called mespophilic meadows that are neither too dry or too moist. This plant, once picked, was threatened. It is now out of danger but will require, like other species, much respect on your part.
Pastoralism
Agricultural decline
Ÿou will notice on both sides of the trail, towards the Randolière, numerous small cembro pines, established in the middle of the pastures. Whereas the entire slope was once grazed and mown, the gradual disappearance of small farm holdings and the change in practices have encouraged this forest species to recolonise the area. Over time, if agriculture were to disappear, it’s in the forest that you would find yourself. The loss of these pasture lands will lead to a decline in biodiversity.
Viewpoint
Lakes of the Aussois dam
Downhill behind you, you will be able to see the lakes of the Aussois dams. The Plan d’Amont is remarkable for its turquoise colour, fed only by the melting snows and clear streams. Downstream, the Vanoise glaciers feed the lake thanks to 19 km of underground tunnels originating from the Doron de Termignon. The water is loaded with glacial “flour”, fine mineral particles torn from the mountains. This is what gives the Plan d’Aval its grey, milky colour.
Fauna
The common rock thrush
This colourful bird did not escape from a garden centre. Despite spending its winter in Sub-Saharan Africa, the common rock thrush regularly inhabits the dry rocky and sunny slopes of our mountains to breed. While it can feed on small lizards and seeds or fruit, it gains most benefit from the abundance of various insects. At the end of summer, it will return to its wintering areas. The common rock thrush has been on the decline in France for several years with about 1,500 breeding pairs left only in France. It is a spectacle to see, so keep a keen eye.
Flora
The Silene acaulis
This cushion, punctuated by bright pink flowers, is not a moss. The silene acaulis is one of the champions of adapting to the worst. The cushion-like form allows it to reduce day-time and night-time temperature variations that can be significant at these altitudes. Moisture will also be trapped in this hairy, small-leaved stem. The ancient decomposed leaves of the silène acaulis contain nutrients that will allow it to grow and to bloom. A taproot in the cushion’s core will allow it to cling to the steepest terrain.
Fauna
The mountain hare
Also known as the white hare, it has a rock-brown coloured coat in the summer and an all-white coat in the winter except for the tips of its ears. Smaller and rounder than the European hare, the mountain hare also has shorter ears and a thicker coat to limit heat loss. Its wider back paws act as snowshœs which allow it to move easily over the snow.
Flora
Persicaria vivipara
In the midst of the sand and rock, a stem loaded with small white flowers appears. The persicaria vivipara grows here. Some plants germinate and develop in the fruit while the latter is still attached to the stock plant. This phenomenon corresponds to vegetative viviparity. If you examine the persicaria vivipara, you will see small green bulbs attached to the stem. The fruits of the persicaria vivipara then begin to germinate on the plant. The seeds of the persicaria vivipara are a delicacy for the rock ptarmigan.
Geology
Snowy paving
Look around you for flat, damp areas without vegetation. Ÿou are bound to notice that the rock slabs seem to have been sorted and patiently arranged, one against the other. Man is not responsible for this geometric pattern. Here, the alternating freezing and thawing cycles and the weight of the snow encourage the transport of stones and their alignment to create what we call snowy paving. In other cases, these phenomena may create polygonal grounds or stone circles.
Geology
The filling of wetlands
As you descend from the lake, you will notice the grassy and flat stretches of terrain. The ancient glacier has gouged out depressions in the bedrock. When the ice retreated, these areas became lakes. Just like the Lac du Génépy, alluvium has filled these depressions, the hygrophilous vegetation then colonised these wetlands. Some of these areas then dried up to become small grassy plateaus amid the ´rocky ground´.
Flora
The dwarf willow
Perhaps you have unintentionally trampled over its small, green and shiny oval leaves? Like Gargantua, you were walking over a forest! The dwarf willow (Salix herbacea) is the smallest tree in the world. Like other willows, its flowers will come together in catkins and cover the rocks with a fine cottony layer in July and August. The male and female flowers are on separate plants.
Fauna
The rock ptarmigan
The Rock ptarmigan, known simply as the ptarmigan is an arctic-alpine bird. Indeed, its area of presence has followed the thawing prehistoric glaciers towards northern Europe and at altitude. In the Alps, it is found only above 2,300 m altitude. In order to escape from its predators, the ptarmigan becomes white in winter and in summer its plumage takes on the colours of the rocky ground and shallow grasses that it favours. As a mainly flightless bird, evolution has covered its talons in feathers to prevent heat loss, allowing it to move over snow, effectively giving it snowshœs.
Geology
The Lac du Génépy and its moraine
If you think you will discover a clear expanse of water when you arrive at the lake, you will be surprised. The Lac du Génépy is a glacial lake. At the end of the little ice age (1550-1850) the Labby glacier left a moraine on the right bank of the lake. A moraine is an accumulation of stones transported along the front of the glacier and left in place during its retreat. The glacier gouges out the rock in front of the moraine. The glacial meltwater occurs in this basin, creating the Lac du Génépy. The very fine mineral particles that you can touch on the shores of the lake fill it gradually and give it its milky colour.
Small heritage
The Cabane de Labby
The Vanoise National Park is monitored by rangers in every season. They collect data essential to the knowledge of flora and fauna, monitor the territory and welcome and provide information to hikers. For these missions, the park rangers can count on a network of surveillance cabins scattered throughout the heart of the park. Standing before you, the Cabane de Labby, is one of them.
Geology
The Fond d’Aussois
As you begin the steep descent to the Fond d´Aussois, look out for this example of a large-scale glacial basin. Imagine for a moment the glacier descending from the Col d’Aussois: its flow is slowed by the narrowing of the valley, further increasing its erosive power. A depression is created. As the ice melts, a lake is created and fills by accumulating fluvio-lacustrine alluvium. Once completely filled, the site of the lake is occupied by a very flat plain where the Saint Benoit stream gently flows today.
Geology
Fond D’Aussois Basin
A glacial basin is the name give to the area dug out by a glacial valley. Once the glacier recedes, this depression is generally occupied by a lake of variable size which gradually fills up with fluvio-lacustrine alluvium until it forms a plateau. Here, certain areas retain their swamp-like properties with typical plants such as swertia perennis. These rich and flat grasslands have long been appreciated for livestock farming as evidenced by the presence of old alpine huts.
Fauna
Marmots
Belonging to the squirrel family, marmots occupy the plateau in small family groups. Ÿou can spot them eating as, having become accustomed to passing hikers, they are not timid. Ÿou can hear their shrill screams echoing in the mountain as they alert their fellow-mates to the presence of any predators. Marmots are born in June in the shelter of their family burrow. It’s only in July that you will be able to see them.
Small heritage
Vanoise National Park
“Here there is space. Here there is pure air. Here there is silence. The kingdom of flawless dawns and naive beasts...”. It was with these words that Samivel wrote the commandments of the National Park upon its creation in 1963. Ÿou enter a protected area, “the great garden of the French” which it is your responsibility to protect. The regulations are displayed on the various panels intended for hikers.
Flora
The cembra pine
The pinus cembra is comprised of the cembro or arolla pine. The hardwood is used in cabinet-making. Its long needles, in ascicles of five, make it easily recognisable. Mountaineers consume the cones or seeds, competing with the spotted nutcracker. The cembro pine climbs up to 2,300 m and is fond of acid soil and varied orientations. Together with the rhododendron, bilberries and cranberries, it constitutes the forest boundary.
Architecture
The Plan d’Amont Dam
Built at the end of the Second World War to meet the country´s energy needs, its clear waters cover a valley formerly used for agropastoralism. With the Plan d’Aval Dam, it was originally conceived as a set of three dams which should have flooded the valley of Fond d´Aussois. The construction of the two dams required the creation of a quarry for extracting materials, which has now been turned into the car park. These sites contain a vast underground network of water pipes.
Flora
Rhodora
This shrub adorns the mountain with the most beautiful colours from mid-June until the end of July. In Greek, Rhododendron means “red tree” and its ferruginous qualities come from the rusty colour of the underside of its leaves. The rhododendron finds it is perfectly at home on the slopes where the snow persists and thereby offers it protection against the frost.
Description
"From the car park, follow the route of the Refuge de la Dent Parrachée. Behind it, the trail is indicated by the National Park’s yellow signs.Follow the direction for ""Lac du Génépy"". After about 30 minutes, cross the footbridge and continue the trail to the lake. To return, follow the same path. Just before the Refuge de la Dent Parrachée, turn right towards the Fond d´Aussois. Be careful, after 300 m, a short passage requires vigilance. Follow the trail to a footbridge that you leave on its right and continue south to the GR5 intersection. Then turn right and go down to the bridge you have to cross, follow the direction for Aussois until the Plan d´Amont dam from where you reach the car park."
- Departure : Dam site, village of Aussois
- Arrival : Dam site, village of Aussois
- Towns crossed : AUSSOIS
Altimetric profile
Recommandations
High mountain route to be prepared in advance. Make sure you have the appropriate equipment and footwear and an IGN map for navigating. The weather in the mountains can change very quickly and you should turn around if it is bad.
Is in the midst of the park
The national park is an unrestricted natural area but subjected to regulations which must be known by all visitors.
Information desks
Maison Cantonale<br>9 Place Sommeiller<br>73500 Modane,
http://www.cchautemaurienne.com/
info@cchmv.fr
04 79 05 26 67
43 route des Barrages<br>73500 Aussois,
http://www.aussois.com
info@aussois.com
04 79 20 30 80
Transport
"
Rail connection to Modane. Information: www.voyages-sncf.com
Then transport by coach to the administrative centre of Aussois. Information: www.transavoie.com
No public transport between Aussois and the dam site.
Suggested hitchhiking organised in the Haute-Maurienne valley. Information: www.rezopouce.fr
"Access and parking
In Modane, take the D 215 towards Aussois. Once you’ve arrived in Aussois, go to the top of the village and take the small road that rises towards the dams. Leave a panoramic viewpoint on the left and take a steep road on the right for 100 m to reach the car park.
Parking :
Car park provided by the municipality for the entire dam site, departure point for all hikes.
Accessibility
The terminal car park is equipped with amenities but is not beyond the trail described in this record.
Emergency number :114
