French Alps :
Where to go?
The mountain range of the Alps – the highest in Europe – stretches along a curved line from Nice on the Mediterranean coast to Vienna in Austria, covering a distance of 1 200km/750mi. The French Alps extend from Lake Geneva to the Mediterranean, a distance of 370km/230mi, and they are over 200km/125mi wide at their widest point, between the Rhône Valley and the Italian Piedmont. The highest peak, Mont Blanc, rises to 4 807m/15 771ft, but the altitude gradually decreases towards the south and the range is easily accessible through a series of deep wide valleys.
The region is famed for magnificent views which appear to change with every bend of the steep, winding roads. It is an area full of contrasts from the colourful shores of Lake Geneva to the glaciers of Mont Blanc, the chalk cliffs of Vercors and the dry Mediterranean landscapes of Haute-Provence.
Geologists divide the French Alps into four main areas:
– The Préalpes, or alpine foothills, consisting almost entirely of limestone rocks formed during the Secondary Era, except in the Chablais area.
– The Alpine trench, a depression cut through marl, lying at the foot of the central massifs.
– The central massifs, consisting of very old and extremely hard crystalline rocks. The tectonic upheavals of the Tertiary Era folded the ancient land mass, creating “needles” and high peaks, which are the highest of the whole Alpine range. From north to south, these massifs are: the Mont-Blanc, Belledonne, Grandes Rousses, Écrins and Mercantour.
– The intra-Alpine zone,forming the axis of the Alps. It consists of sedimentary rocks transformed and folded by the violent upheavals which took place in the area. It includes the Vanoise, the Briançonnais and the Queyras as well as the upper valleys of the Tarentaise, the Maurienne and the Ubaye.
Formation of the Alps
Among the “younger” of the Earth’s mountains, formed at roughly the same time as the Pyrenees, the Carpathians, the Caucasus and the Himalayas, the Alps are also one of the most geographically complex ranges. Long before the folding of the peaks some 65 million years ago, and the erosion by water, wind and ice which continues to this day, powerful forces were at work beneath the surface.
To explain the phenomenon of geological upheaval that has formed the Alps, we turn to the concept of plate tectonics, which describes the earth’s crust as a series of rigid plates moving in relation to one another. The Alps are situated at the boundary of the African and European plates. During the Paleozoic Era, 540–250 million years BP, a huge folding of the Earth’s crust produced the Hercynian mountains, which had a crystalline structure similar to that of the Vosges and the Massif Central today. The luxuriant vegetation, stimulated by the hot and humid climate, produced a huge amount of plant deposits that are the origin of coalfields at La Mure and in the Briançonnais. Erosion followed, and after 200 million years the crystalline foundation was submerged under the sea, and a layer of marine sediments thousands of metres thick was formed.
The Mesozoic Era, 250–70 million years BP saw the land compressed by the African continent, which was moving to the north. The seabed deposits of limestone and sand (which were transformed into sandstone when compressed) as well as clay (which under high pressure often flaked into shale) piled up on the ancient foundation of crystalline rocks. The climate was uniform; forests consisted of pines, oaks, walnut trees, eucalyptus and palm trees. Huge reptiles such as dinosaurs roamed the earth and the first birds appeared.
The Tertiary Era, 65–1.8 million years BP, saw the formation of the high range of mountains we see today. Starting about 30 million years BP, a spur of the African plate, consisting of Italy and part of the Balkans, advanced and collided with Europe, pushing up masses of schist, folding the area like plasticine, and forming the Italian Alps and the Vanoise to the east, Chablais to the west and, to the north, the Swiss Alps.
More recently, 10–5 million years BP, the continuing force of the African plate pushed up the ancient crystalline foundation from under the seabed deposits of limestone, marl and clay; this layer literally came unstuck and began to slide westwards in spectacular folds, creating the Préalpes.
A depression appeared between the crystalline massifs and the Préalpes, which eventually became the Alpine trench through the work of erosion. Most recently, in the last few millions of years, the Dauphinois and Savoy areas were covered by shallow inland seas, where a layer of sediment accumulated from erosion of the nearby mountains, forming the gentle, fertile countryside of Albanais and Geneva.
A general cooling of the earth’s atmosphere over the last 2.5 million years caused by the rise of the Himalaya and the Isthmus of Panama, has brought about a series of glacial periods during which the whole alpine region was covered with a huge mantle of ice. Erosion then worked relentlessly on a complete remodelling of the Alps into the mountain range it is today.
These vary considerably according to the different geological structure of each area. So, it is logical to adopt the geologists’ division of the Alps into four parts preceded by what we might call the Alpine fringe. From west to east and south to north, they are the Préalpes, the Alpine trench, the central massifs and the intra-Alpine zone.
The Albanais, the Geneva area and the Bornes Plateau situated on the edge of the northern Alps offer landscapes of green rolling hills dominated by a few moderate mountain ranges such as the Salève south of Geneva and the Mont du Chat near the Lac du Bourget. The basins left behind by retreating glaciers have been filled in by deep lakes: Lac d’Aiguebelette and Lac du Bourget.
The northern Préalpes lie just beyond the Alpine fringe along a north–south axis, forming a barrier which rarely rises above 2 500m/8 202ft. They consist of five distinct massifs carved out of limestone (except for the Chablais), separated by transverse valleys: the Arve, Annecy, Chambéry and Grenoble.
Overlooking Lake Geneva and drained by the three Dranse rivers, the Chablais is backed by the Giffre with its lively winter resorts, Samoëns and Flaine.
The Bornes massif, flanked by the Chaîne des Aravis in the east, is drained by several rivers including the Fier and extends from the valley of the Arve to the blue waters of lac d’Annecy.
Further south, the Bauges massif, extending to the Cluse de Chambéry, offers pleasant pastoral landscapes.
The Chartreuse massif, with the Cluse d’Isère to the south, stands like an imposing limestone fortress; features include high cliffs, deep gorges, valleys with pastures and magnificent dense forests on the well-watered slopes.
The Vercors is the largest of the Préalpes massifs; within its impressive outer ramparts, this natural citadel offers beautiful forest and pastoral landscapes, as well as striking gorges and popular resorts such as Villard-de-Lans.
The southern Préalpes spread over a vast area along a curved line in a northwest-southeast direction. The Durance Valley divides them into two groups. West of the river, on the Dauphiné side, is the wild and austere Dévoluy, with its cliffs and bare summits below which sheep and cattle graze. The wooded Bochaine marks the transition between north and south whereas the Diois and Baronnies already offer typical southern landscapes where soaring limestone peaks collapse into waves of rock set in conflicting directions. To the south, the limestone massif of Mont Ventoux stands alone, towering 1 909m/6 263ft above the Avignon Basin.
East of the Durance, the relief becomes more intricate, without any apparent plan; the mountain ranges of the Préalpes de Digne and Préalpes de Castellane are cut crosswise by deep wild gorges guarded by picturesque towns like Sisteron, Digne and Castellane. These areas are the least populated of the Alpine region. Because of strict conservation regulations, the slopes have retained their varied vegetation, but the summits are mostly bare.
Lying between the River Verdon and River Var, the Préalpes de Grasse rise to an altitude varying between 1 100m/3 609ft and 1 600m/5 250ft.
The Préalpes de Nice are deeply cut in a north-south direction by rivers (Var, Tinée, Vésubie) which make their way to the sea through impressive gorges overlooked by villages perched high above the river beds.
Lying between the Préalpes, the Plateau de Valensole occupies the former delta of the River Durance filled in by an accumulation of rocks from nearby mountains. These rocks and pebbles, bound together by a kind of natural cement, form a conglomerate which has been carved by erosion into the famous Pénitents des Mées. Further east, there are several limestone plateaux through which streams penetrate and disappear into sink-holes. Spectacular gorges have been carved out by the River Verdon and River Artuby.
In the northern Alps, the Bassin de Sallanches and the Val d’Arly form, together with the depression of the Combe de Savoie and Grésivaudan, a wide longitudinal plain into which open the upper valley of the River Isère (Tarentaise) and the valleys of the Arc (Maurienne) and of the Romanche (Oisans). Owing to the means of communication provided by this internal plain, to the fertile soil which favours rich crops (maize, tobacco, vines) and to the availability of hydroelectric power, the Alpine trench has become one of the most prosperous areas of the region.
In the southern Alps, a similar depression runs along the foot of the Écrins, Briançonnais and Queyras massifs; the River Durance and its tributaries flow through this relatively flat area partly flooded by the artificial Lac de Serre-Ponçon. Some strange rock formations, carved out of ancient moraines, can be seen in this region. They stand like groups of columns and are known as Demoiselles coiffées (capped maidens) because they are crowned by a piece of hard rock. Between Sisteron and Manosque, the fertile Durance Valley brings Provence, its typical vegetation and orchards to the heart of the southern Alps.
This central mountain range includes Mont-Blanc, the Aiguilles Rouges,the Beaufortain, the Belledonne, the Grandes Rousses, the Écrins-Pelvoux and, in the south, the Mercantour.Together, these massifs, rising to over 4 000m/13 123ft, form the high Alps, consisting of hard crystalline rocks, which were uplifted during the Tertiary Era while their sedimentary cover was removed. The Beaufortain is the only massif to have retained its layers of schist: it offers pleasant pastoral landscapes scattered with wooden chalets. Beautiful lakes have filled in the basins left by the glaciers.
Situated between the central massifs and the Italian border, the Vanoise Massif and the Briançonnais-Queyras Massif also belong to the high Alps, but they consist of a mixture of schist and metamorphic crystalline rocks. Valleys are deep and slopes are turned to pasture. Thanks to its mild, sunny climate and snow-covered slopes, the Vanoise (which has the Tarentaise and Maurienne as natural boundaries and includes the Parc national de la Vanoise) has the highest concentration of winter resorts in the French Alps, embracing Val-d’Isère, Tignes, Courchevel, La Plagne, Méribel-les-Allues and Les Arcs.
Due to the diversity of its rock structure, the Briançonnais-Queyras Massif has a more complicated relief: sandstone, limestone and schist carried over from the Italian side as a result of overthrust. Its characteristic southern light, blue skies and generous sun make this area one of the healthiest in Europe, which explains the rapid development of summer and winter tourism centred round high villages such as St-Véran (2 040m/6 693ft).
The Gap, Embrun and Ubaye districts, lying between the high Alps and the Préalpes, offer a mosaic of heights, small basins and wide valleys carved out of layers of “black soil”, or flysch in the case of the Ubaye.
The slow but irresistible action of glaciers, rivers, rain and frost has completely remodelled the Alps over thousands of years into the mountain range it is today.
The action of the glaciers – Around 10 000 years ago, glaciers covered the whole Alpine range and spread over the adjacent flat areas as far as Lyon. Some of these “solid rivers” were huge, reaching thicknesses of 1 100m/3 609ft in the Grésivaudan for instance. They scooped out cirques with steep back walls and dug U-shaped valleys characterised by successive narrowings and widenings and a series of steps, with tributary valleys “hanging” over the main ones.
Alpine glaciers today – Since the beginning of the 20C, Alpine glaciers have been consistently receding because they are not being sufficiently renewed, and today they only cover an area of 400km/154sq mi; four fifths of them are in Savoie (Mont-Blanc and Vanoise), the remainder being in the Écrins Massif.
The Mer de Glace is a very good example of a “valley glacier.” Moving downstream, we find in succession a névé, an expanse of snow not yet turned into ice, and a glacial “tongue” cut by deep crevasses. Level changes are marked by jumbled piles known as séracs; accumulations of debris carried down by the glacier are called lateral moraine when deposited on the edges, terminal moraine when deposited at the end and medial moraine when deposited between two joining glaciers.
Erosion by water – When the ice mantle disappeared, mountain streams and rivers began to smooth out the relief. Connecting gorges opened up the “bolts” and joined the floor of a “hanging” valley to that of the main valley. These valleys, wide but often closed off, like that of Chamonix for example, would be completely isolated but for audacious road construction. There are gorges of another kind, mainly in the Préalpes, which cut across the axis of the folds: they are called cluses (transverse valleys). They are often the only means of communication between the mountain and the lower areas. The most active mountain streams deposit debris they have been carrying when they reach the bottom of the main valley and their accumulation at the foot of the slopes forms alluvial cones which obstruct the valleys.
Streams and Rivers
The southern Alps have three distinct river networks: in the centre the Durance and its tributaries, in the east the Var which gathers water streaming down the Alpes Maritimes, and in the west the tributaries of the Rhône.
Mediterranean rivers are particularly interesting because they behave like real mountain streams. During the summer, they are reduced to a trickle owing to the absence of rain and intensive evaporation, but in spring and autumn, violent rain storms or sudden thaws fill up the river beds so suddenly that the flow of foaming water tumbles down at the speed of a galloping horse. The rate of flow of the River Var, for instance, varies from 17m/600cu ft per second to 5 000m/176 575cu ft per second. The Durance, Verdon, Aigues and Ouvèze rivers are much the same. However, the Durance and Verdon have been harnessed by dams (Serre-Ponçon across the Durance, Castillon and Ste-Croix across the Verdon) and canals. The impressive gorges dug by these rivers (Grand Canyon du Verdon, Gorges du Cians) are one of the main attractions of Haute-Provence.
Underground streams forming mysterious hydrographic networks sometimes reappear further on; streams from the Montagne de Lure, for instance, feed the spectacular resurgent Fontaine-de-Vaucluse.
The Alpine range is divided into two distinct climatic regions: the northern Alps which are subject to west winds off the Atlantic, and the southern Alps which enjoy a Mediterranean climate. The separation between these two regions follows a line drawn from west to east between high mountain passes: Col de Rousset, Col de la Croix Haute, Col du Lautaret and Col du Galibier.
Rainfall over the northern Alps is abundant all year round and temperatures are low. The Préalpes and central massifs get the brunt of the rainy weather. The intra-Alpine zone, protected by these barriers, is drier and sunnier; snow remains on the slopes longer. However, many factors such as altitude, aspect and the general direction of the various ranges and valleys, contribute to create a great variety of microclimates.
Altitude – Temperatures fall rapidly as the altitude increases (roughly 1°C/3°F every 100m/328ft); interestingly, this phenomenon can be reversed in winter, during periods of settled weather, as cold, heavier air slips down the slopes and accumulates in the valleys and the warm air rises.
Relief – It has an influence on rainfall and wind direction; rain and snow fall more generously on the first heights in their path and on slopes exposed to the wind. Winds generally blow along wide valleys, particularly during the warm season when, towards midday, warm air rises from the valleys and causes clouds to form round the summits. This is a sign of continuing fine weather. Later on in the day, the process is reversed and a cold mountain breeze blows down into the valleys. Heights usually attract storms which are often violent and spectacular.
The climate enjoyed by the southern Alps displays typical Mediterranean features: a good deal of sunshine, dry weather, clear skies, the absence of mist or fog, rare yet abundant precipitation and the famous mistral wind. In winter there is a fair amount of snow and plenty of fine weather in which to enjoy it. Spring is characterised by a short rainy spell while the mistral blows hard from the southwest. Summer is hot and dry over the whole of Haute-Provence and the air filled with the delicate scent of lavender and thyme. Nearer the summits, temperatures are more moderate. In the autumn, violent storms are succeeded by sunny spells, the air is pure and the light ideal for discovering the beauty of nature.
In mountain areas, the pattern of vegetation is not only influenced by the climate and the type of soil, but also by aspect and altitude, which define a succession of vertical stages. This staging is modified by man who has done much to alter original landscapes. South-facing slopes, which offer the best conditions for settlement and agriculture, have been subject to deforestation, while northern slopes, often uninhabited, have retained their trees; a pattern seen at its best in valleys running from east to west.
Slopes are usually farmed up to an altitude of about 1 500m/5 000ft; above this there is a belt of conifer forest. From around 2 200m/7 000ft upwards, the trees give way to Alpine pastures with their rich mixture of wild grasses and Alpine flora. Above 3 000m/10 000ft, bare rock prevails, with mosses and lichens clinging to it in places.
The Alps are famous for their forests of conifers. Old fir trees have broad crowns with flattened points looking like storks’ nests. The bark is greyish; the cones, standing up like candles, break up when ripe and shed their scales. The soft needles are lined up like the teeth of a comb and have a double white line on their inner surface. The spruce is the most common tree on north-facing slopes. It has a pointed, spindle-shaped crest and drooping branches, and its reddish bark becomes deeply fissured with age. It has sharp needles and its hanging cones fall to the ground in one piece when ripe. The only conifer in the French Alps to shed its leaves in winter, the larch is commonly found growing on south-facing slopes, particularly in the “Alpes sèches” (dry Alps). The cones are quite small. The delicate, light-green foliage casts relatively little shade, thus favouring the growth of grass, one of the attractive features of larch woods, while the dropped needles create an acidic soil that favours rhododendrons and bushes such as blueberries. The many species of pine all have needles growing in tufts of two to five encased in scaly sheaths. The forest pine, with its tall slender trunk, grows in considerable numbers in the southern Alps, usually on the sunny slopes.
The grey-trunk beech prevails in the Préalpes to an altitude of 800m/2 625ft. With its thick boughs it provides shade for many rare plants, including Turk’s-cap lily, belladonna or deadly nightshade and speedwell. Among other deciduous trees, there are alders, maples, birches, service trees, willows and laburnums with their lovely clusters of yellow flowers.
Trees – Several varieties of oaks and pines, as well as almond trees and the typically Provençal cypress and olive grow in the southern Alps, either in cultivated areas or scattered on dry, rocky moors known as garrigue. Such landscapes can be seen in the Durance Valley, on the southern slopes of Mont Ventoux or the Montagne de Lure and in the Baronnies and Diois areas. Further north, above 600–800m/1 968–2 625ft, forests of white oaks, forest pines and beeches prevail, particularly on north-facing slopes. Such forests often alternate with heaths where gorse, box and lavender grow.
The evergreen holm oak has a short, thick-set trunk with a wide-spreading dome and fine, dark green leaves. It grows on calcareous soil at less than 328m/1 000ft; in stunted form, it is a characteristic element of the garrigue.
The deciduous downy or white oak,so-called because the undersides of the leaves are covered with dense short white hairs, requires more water than the evergreen oak. It is found in valleys and on the more humid mountain slopes.
The Aleppo pine, one of the Mediterranean species of pine trees, has a light, graceful foliage and a trunk covered with grey bark, which twists as it grows.
The outline of the dark cypress, a coniferous evergreen, marks the Mediterranean landscape with its tapered form pointing towards the sky, while the common almond tree delights the eye with its lovely early spring pink blossoms.
Garrigue – This word is used to describe vast expanses of rocky limestone moors. Vegetation is sparse, consisting mostly of holm oaks, stunted downy oaks, thistles, gorse and cistus as well as lavender, thyme and rosemary interspersed with short dry grass which provides pasture for flocks of sheep.
The name “Alpine” is normally used to describe those plants which grow above the tree line. Because of the short growing season (July and August), these hardy species flower early, while the disproportionate development and colouring of the flowers is the result of exposure to intense ultraviolet light. Their resistance to drought is often their main characteristic; many have woolly leaf surfaces and thick, water-retaining leaves.
Above the tree line, at high altitudes, animals have learnt how to adapt to the harsh environment, where it is possible to survive only by building up one’s defences against the cold and the lack of food. Some animals are protected against the cold by their thick coat or plumage, others such as the marmot hibernate below ground, so solving the problem of food shortage. The blue hare and the snow-partridge, which are the favourite game of foxes and birds of prey, make themselves inconspicuous by changing colour with the seasons. In winter, large herbivores like bouquetin (ibex) and chamois make their way down to the forests in search of food and shelter. In addition to this struggle for life, these animals must contend with man’s expansion into their habitat: many seem doomed to extinction in the near future except in conservation areas.
Mammals – The bouquetin (ibex), is a stocky wild goat with curved, ridged horns which can be more than a metre long; this peaceful animal enjoys basking in the sun. When snow begins to fall, the males join up with the females who are smaller and shier. The males then fight for the females and the clatter of their horns clashing echoes throughout the mountains.
The chamois, the “Alpine antelope”, has a reddish brown coat, thicker and darker in winter, with a black line on its back. Its small head is surmounted by curved slender dark horns. This strong animal jumps from one rock to the next and climbs the steepest passages; its thin, strong legs and its special hooves explain its extraordinary agility. A chamois can weigh as much as 50kg/110lb. In summer it feeds on grass; in winter it goes down to the forest and nibbles at the bark of trees.
The reddish brown summer coat of the stoat becomes white in winter apart from a thin tuft of black hair at the end of its tail. This small carnivorous mammal lives among stones or near chalets.
The marmot is well suited to the vast parks of the area. Skiers cause it no anxiety at all, since it passes the winter season hibernating under the snow in warm tunnels. From April to September, it enlivens alpine pastures with its whistling call.
You may need a stroke of luck, to catch a glimpse of a lynx stalking the slopes at sunset in search of birds, marmots, chamois and small deer. Virtually extinct in the region by the beginning of the 20C, this wild cat has returned to the woods of Savoie from Switzerland.
The moufflon is a large wild sheep, living in flocks led by the older males. Originally from Asia, but well adapted to the Mediterranean climate and vegetation, it has been introduced into the Mercantour and Queyras nature parks.
Butterflies and moths – There are more than 1 300 different species of butterflies and moths in the Alpes-de-Haute-Provence département alone and more than 600 species in the area around Digne (there is an exceptionally fine collection of lepidoptera in the local museum), among them some 180 butterflies which represent three quarters of the total butterfly population of France. Among the most remarkable species are the Swallowtail butterfly, the Parnassius and, smaller but also rarer, the Diana and the Proserpina, the Jason, the Vanessas and the Érèbiae (including the Scipio, currently becoming extinct) which hover over lavender fields. The destruction of the traditional environment and the development of industries in the area are responsible for numerous species becoming extinct every year.
Birds of Prey – Golden eagles can often be seen throughout the Alps, circling above their territory, which might cover most of a valley. Breeding pairs remain together for life, rearing their young in eyries on the side of inaccessible cliff faces. Eagles prey on marmots in summer and feed off carcasses when food becomes short in winter.
In winter and spring, you may hear, but probably not see, the Tengmalm owl, whose call is long and piercing. It is well adapted to cold and mountain forests. The reintroduction of the bearded vulture, which soars on wings 2.80m/9ft wide from tip to tip, has been a great success story, and you can see a colony of these magnificent birds in the Parc naturel régional de Verdon.