Contenu du sommaire : Risques naturels dans le couloir rhodanien : les excès pluviométriques
Revue |
Géocarrefour Titre à cette date : Revue de géographie de Lyon |
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Numéro | volume 68, no 2-3, 1993 |
Titre du numéro | Risques naturels dans le couloir rhodanien : les excès pluviométriques |
Texte intégral en ligne | Accessible sur l'internet |
- Comité de rédaction - p. 2
- Editorial - Marcel Leroux p. 89-90
- Chronologie des catastrophes pluvieuses dans le sud de la France / Chronology of exceptional rainfall in southern France - Gérard Staron p. 91-100 The southern area of France regularly receives heavy Mediterranean rainfall, chiefly during the autumn in September and October. This occurs particularly over the Cévennes and to a lesser extent over the eastern Pyrenees and the department of Alpes-Maritime. Over other, generally less exposed, regions disasterous events are linked to sudden flooding. This type of episodic occurrence contrasts with normal Mediterranean rainfall ; it is short-lived associated with more intense storm activity and results in a rapid rise in water levels, with damage focused on a particular, vulnerable point.
- Variabilité des précipitations annuelles dans la région Rhône-Alpes : présentation cartographique / Variability of annual rainfall in the Rhône-Alpes region : a cartographic presentation - Guy Blanchet p. 101-109 Presentation of annual precipitation maps of the Rhône- Alpes region : quantiles and the frequencies with which certain thresholds are exceeded.
- Charles Toupet, Le Sahel - Marcel Leroux p. 110
- Evolution pluviométrique récente dans le sud de la vallée du Rhône / Recent rainfall evolution in the southern Rhône valley - Stéphane Aubert p. 111-114 Following the disaster of Vaison-la-Romaine, the question of an abrupt climatic change has again been raised. However, contrary to widespread opinion, the present pattern of rainfall is not exceptional and the succession of catastrophic floods recalls the period 1928-40. Since 1954 a continuous rise in pressure - more regular since 1975 - has been linked with a decrease in rainfall : a strong inverse correlation is observed between surface pressure and rainfall.
- Les pluies azuréennes de septembre-octobre 1992 / Rainfall on the French Riviera in September and October 1992 - Pierre Carrega p. 115-124 Unlike other regions in south eastern France, the French Riviera did not experience catastrophic rainfall in the autumn of 1992. Whether measured on an hourly or daily basis, intensities were nowhere exceptional. However, the frequent occurrence of heavy falls resulted in a very high total rainfall constituting an absolute
- Suivi satellitaire (Météosat) de la situation météorologique des 21,22 et 23 septembre 1992 sur l'Europe occidentale et le proche Atlantique / Satellite imagery (Meteosat) analysis of the meteorological situation over western Europe and the neighbouring area of the Atlantic Ocean on 21, 22 and 23 September 1992 - Michel Erpicum p. 125-127 The METEOSAT 5 satellite imagery shows the movement of cloud formations over France and the adjacent area of the Atlantic between 21 and 23 September 1992. Analysis shows that the heavy rainfall over the Ouvèze river basin represents only an epiphenomenon of a much wider and more comprehensive system.
- Gerard Mottet, Géographie physique de la France - p. 128
- L'épisode pluvio-orageux catastrophique de septembre 1992 dans le sud-est de la France : analyse pluviométrique et météorologique / The catastrophic storms of September 1992 in south eastern France : analysis of rainfall and meteorological conditions - Jean-Claude Deblaere, Guy Blanchet p. 129-138 Exceptional precipitation (up to 300 mm within four hours) hit the South of France on 21 and 22 September 1992 and provoked dramatic flooding of certain tributaries of the Rhône, such as the Ouvèze and the Ardèche rivers. Rainfall characteristics are described and meteorological conditions of this phenomenon are analysed.
- La dynamique des situations météorologiques des 21-22 et 26-27 septembre 1992 dans le sud du couloir rhodanien / The dynamics of the meteorological patterns of 21-22 and 26-27 September 1992 in the southern Rhône corridor - Marcel Leroux p. 139-152 Diluvian rains related to the meteorological patterns of 21 and 22, 26 and 27 September 1992, were the result of the rapid eastward motion of two, early and strong MPHs having a direct meridional path over the Atlantic Ocean. Their power allowed them to move in the form of an airmass over the Iberian relief towards the western Mediterranean, and then to force a strong southerly, warm and moist airstream towards the southern part of France, where highlands amplified the stormy nature of disturbances. The month of September 1992, was characterized by a large number of MPHs with strong meridional paths. These dramatic events are connected with a climatic change governed by a cooling trend over the Arctic Ocean area.
- Les difficultés d'estimation rapide des débits observés en crue : exemple de la crue de l'Ouvèze du 22 septembre 1992 / The difficulties of rapidly estimating flows during a flood : the example of the flooding of the Ouvèze river on 22 September 1992 - Jacques Lavabre, Olivier Gilard, Bernard Chastan p. 153-158 This paper presents some methods used to estimate flows with incomplete data collected immediately after a flood. It highlights the difficulties of such a calculation and shows how to reconcile different methods which seem contradictory. The flood at Vaison-la-Romaine, south of France, on 22 September 1992, is presented as an example.
- Fortes pluies et crues de septembre 1992 sur le bassin cristallin de l'Ardèche en amont d'Aubenas : causes et conséquences / The heavy rainfall and floods of September 1992 in the crystalline river basin of the Ardèche above Aubenas : causes and consequences - Gérard Mottet, Valérie Malhaire, Carole Coste p. 159-169 During the month of September 1992 a storm sequence of considerable intensity (nearly 300 mm of rainfall in 24 hours) was focused over the eastern border of the Massif Central between Les Vans and Cheylard, an area 70 km long and 30 km wide. The rainfall rapidly produced violent flooding of the Ardèche and its tributaries : the waters of the small Fontolière river rose 2 metres in 15 minutes, with an observed flow of 800 m3/s ; the Ardèche itself rose 7 metres at Pont-de-Labeaume. Although the human and material consequences were less serious than those produced by the flooding of the Ouvèze at Vaison- la-Romaine, the flooding of the Ardèche and its tributaries damaged river banks, bridge parapets, camp sites and supermarkets in the area above Aubenas, and killed 4 people. This event forms part of a much more widespread meteorological phenomenon which concerned the Mediterranean region of France at this period.
- Michel Savy, Pierre Veltz, Les nouveaux espaces de l'entreprise - Martin Vanier p. 170
- Les dommages causés à l'agriculture en Vaucluse et dans le sud de la Drôme le 22 septembre 1992 / Damage to agriculture on 22 September 1992 in the Vaucluse and Drôme departments - Jeanne Berenguer p. 171-174 The storms and floods of 22 September 1992 in the southern part of the Drôme department and the northern and central western part of the Vaucluse department, severely damaged crops as well as soils, perennial plantations and farm buildings ; the cost of rectifying the damage increases these regions present economic difficulties.
- Bilan social et économique de la séquence orageuse du 22 septembre 1992 dans le sud du couloir rhodanien / Social and economic consequences of the storms on 22 September 1992 in the southern Rhône corridor - Jacques Comby p. 175-192 The catastrophe which occurred at Vaison-la-Romaine after the heavy downpours of 21 and 22 September 1992 focused public sympathy on this commune in the department of Vaucluse. However, a socio-economic assessment of this event shows that damage was severe in other areas, particularly in three departments of the Rhône valley, and affected both public and private property. Five months later it is difficult to evaluate the long-term consequences of these events due to the numerous factors which influence the economic revival of the disaster-stricken regions.
- Un exemple de catastrophe hydrologique évitée : l'obstruction de l'Arc par la crue du torrent de l'Envers en juin 1992 / An example of the avoidance of a hydrological catastrophe : the blocking of the Arc by the flooding of the Envers torrent in June 1992 - Alain Marnezy p. 193-202 On 2 June 1992 the Envers torrent (in the commune of Sollières-Sardières in Savoie) experienced a new flood with a heavy torrential charge. Material damage was relatively limited, but debris blocked the river bed of the Arc causing the formation of a dam lake. Action by the Department's engineering services enabled the rapid emptying of the lake. Heavy rainfall provokes the formation of a torrential lava, although the basic condition for this to occur is the availability of loose material. The Savoie Service for the Restoration of Mountainous Terrain considers it is impossible to carry out further corrective work on the river basin itself due to the extreme instability of the slopes. As a result it is proposed to create a depositional platform on top of the dejection cone.
- Chronique : Trente ans de présence française au Spitsberg (1963-1993) / Thirty years of French presence in Spitsberg (1963-1993) - Thierry Brossard, Charles-Pierre Peguy p. 203-205